From 11f12da0525c8a0029bb986de7dd73ddaef23354 Mon Sep 17 00:00:00 2001
From: Rob Pike <r@golang.org>
Date: Wed, 13 Aug 2014 09:00:28 -0700
Subject: [PATCH] go.sys/unix: implement the environment functions by wrapping
 syscall The environment is global state that is owned by the standard syscall
 package. With this change, go test passes on darwin in the unix directory.

LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/129900043
---
 unix/env_unix.go | 102 +++--------------------------------------------
 1 file changed, 5 insertions(+), 97 deletions(-)

diff --git a/unix/env_unix.go b/unix/env_unix.go
index c630bdab..45e281a0 100644
--- a/unix/env_unix.go
+++ b/unix/env_unix.go
@@ -8,112 +8,20 @@
 
 package unix
 
-import "sync"
-
-var (
-	// envOnce guards initialization by copyenv, which populates env.
-	envOnce sync.Once
-
-	// envLock guards env and envs.
-	envLock sync.RWMutex
-
-	// env maps from an environment variable to its first occurrence in envs.
-	env map[string]int
-
-	// envs is provided by the runtime. elements are expected to be
-	// of the form "key=value".
-	envs []string
-)
-
-// setenv_c is provided by the runtime, but is a no-op if cgo isn't
-// loaded.
-func setenv_c(k, v string)
-
-func copyenv() {
-	env = make(map[string]int)
-	for i, s := range envs {
-		for j := 0; j < len(s); j++ {
-			if s[j] == '=' {
-				key := s[:j]
-				if _, ok := env[key]; !ok {
-					env[key] = i
-				}
-				break
-			}
-		}
-	}
-}
+import "syscall"
 
 func Getenv(key string) (value string, found bool) {
-	envOnce.Do(copyenv)
-	if len(key) == 0 {
-		return "", false
-	}
-
-	envLock.RLock()
-	defer envLock.RUnlock()
-
-	i, ok := env[key]
-	if !ok {
-		return "", false
-	}
-	s := envs[i]
-	for i := 0; i < len(s); i++ {
-		if s[i] == '=' {
-			return s[i+1:], true
-		}
-	}
-	return "", false
+	return syscall.Getenv(key)
 }
 
 func Setenv(key, value string) error {
-	envOnce.Do(copyenv)
-	if len(key) == 0 {
-		return EINVAL
-	}
-	for i := 0; i < len(key); i++ {
-		if key[i] == '=' || key[i] == 0 {
-			return EINVAL
-		}
-	}
-	for i := 0; i < len(value); i++ {
-		if value[i] == 0 {
-			return EINVAL
-		}
-	}
-
-	envLock.Lock()
-	defer envLock.Unlock()
-
-	i, ok := env[key]
-	kv := key + "=" + value
-	if ok {
-		envs[i] = kv
-	} else {
-		i = len(envs)
-		envs = append(envs, kv)
-	}
-	env[key] = i
-	setenv_c(key, value)
-	return nil
+	return syscall.Setenv(key, value)
 }
 
 func Clearenv() {
-	envOnce.Do(copyenv) // prevent copyenv in Getenv/Setenv
-
-	envLock.Lock()
-	defer envLock.Unlock()
-
-	env = make(map[string]int)
-	envs = []string{}
-	// TODO(bradfitz): pass through to C
+	syscall.Clearenv()
 }
 
 func Environ() []string {
-	envOnce.Do(copyenv)
-	envLock.RLock()
-	defer envLock.RUnlock()
-	a := make([]string, len(envs))
-	copy(a, envs)
-	return a
+	return syscall.Environ()
 }