174 lines
3.1 KiB
Go
174 lines
3.1 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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//go:build unix || (js && wasm) || plan9 || wasip1
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// Unix environment variables.
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package syscall
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import (
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"runtime"
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"sync"
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"github.com/goplus/llgo/c"
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"github.com/goplus/llgo/c/os"
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)
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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
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// be of the form "key=value". An empty string means deleted
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// (or a duplicate to be ignored).
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envs []string = runtimeEnvs()
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)
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func runtimeEnvs() []string {
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ret := make([]string, 0, 8)
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cenvs := os.Environ
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i := 0
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for {
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ce := *c.Advance(cenvs, i)
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if ce == nil {
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return ret
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}
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ret = append(ret, c.GoString(ce))
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i++
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}
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}
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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 // first mention of key
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} else {
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// Clear duplicate keys. This permits Unsetenv to
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// safely delete only the first item without
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// worrying about unshadowing a later one,
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// which might be a security problem.
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envs[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 Unsetenv(key string) error {
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envOnce.Do(copyenv)
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envLock.Lock()
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defer envLock.Unlock()
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if i, ok := env[key]; ok {
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envs[i] = ""
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delete(env, key)
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}
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os.Unsetenv(c.AllocaCStr(key))
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return nil
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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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/* TODO(xsw):
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func Getenv(key string) (value string, found bool) {
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ret := os.Getenv(c.AllocaCStr(key))
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if ret != nil {
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return c.GoString(ret), true
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}
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return "", false
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}
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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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// On Plan 9, null is used as a separator, eg in $path.
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if runtime.GOOS != "plan9" {
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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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}
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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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os.Setenv(c.AllocaCStr(key), c.AllocaCStr(value), 1)
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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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os.Clearenv()
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env = make(map[string]int)
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envs = []string{}
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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, 0, len(envs))
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for _, env := range envs {
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if env != "" {
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a = append(a, env)
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}
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}
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return a
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}
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