From 565f5c8c5e5f8cf2f8a92cf9375f2f1c0e3ea034 Mon Sep 17 00:00:00 2001
From: Michael Schurter <schmichael@hashicorp.com>
Date: Wed, 16 Aug 2017 14:54:50 -0700
Subject: [PATCH 1/2] Alter subprocess's environment instead of the hosts

Fixes #415
---
 internal/common/common_linux.go | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/internal/common/common_linux.go b/internal/common/common_linux.go
index c0aa9c7..5347b60 100644
--- a/internal/common/common_linux.go
+++ b/internal/common/common_linux.go
@@ -9,15 +9,24 @@ import (
 )
 
 func DoSysctrl(mib string) ([]string, error) {
-	err := os.Setenv("LC_ALL", "C")
-	if err != nil {
-		return []string{}, err
+	hostEnv := os.Environ()
+	foundLC := false
+	for i, line := range hostEnv {
+		if strings.HasPrefix(line, "LC_ALL") {
+			hostEnv[i] = "LC_ALL=C"
+			foundLC = true
+		}
+	}
+	if !foundLC {
+		hostEnv = append(hostEnv, "LC_ALL=C")
 	}
 	sysctl, err := exec.LookPath("/sbin/sysctl")
 	if err != nil {
 		return []string{}, err
 	}
-	out, err := exec.Command(sysctl, "-n", mib).Output()
+	cmd := exec.Command(sysctl, "-n", mib)
+	cmd.Env = hostEnv
+	out, err := cmd.Output()
 	if err != nil {
 		return []string{}, err
 	}

From 042305ee4a0dbd98e1fc106283bbe47e397e9d7e Mon Sep 17 00:00:00 2001
From: Michael Schurter <schmichael@hashicorp.com>
Date: Wed, 16 Aug 2017 15:32:21 -0700
Subject: [PATCH 2/2] Remove SetEnv on all platforms

---
 internal/common/common.go         | 16 ++++++++++++++++
 internal/common/common_darwin.go  |  9 +++------
 internal/common/common_freebsd.go |  8 +++-----
 internal/common/common_linux.go   | 13 +------------
 internal/common/common_openbsd.go |  8 +++-----
 internal/common/common_test.go    | 32 ++++++++++++++++++++++++++++++++
 6 files changed, 58 insertions(+), 28 deletions(-)

diff --git a/internal/common/common.go b/internal/common/common.go
index df71688..1ef9e27 100644
--- a/internal/common/common.go
+++ b/internal/common/common.go
@@ -358,3 +358,19 @@ func Pipeline(cmds ...*exec.Cmd) ([]byte, []byte, error) {
 	// Return the pipeline output and the collected standard error
 	return output.Bytes(), stderr.Bytes(), nil
 }
+
+// getSysctrlEnv sets LC_ALL=C in a list of env vars for use when running
+// sysctl commands (see DoSysctrl).
+func getSysctrlEnv(env []string) []string {
+	foundLC := false
+	for i, line := range env {
+		if strings.HasPrefix(line, "LC_ALL") {
+			env[i] = "LC_ALL=C"
+			foundLC = true
+		}
+	}
+	if !foundLC {
+		env = append(env, "LC_ALL=C")
+	}
+	return env
+}
diff --git a/internal/common/common_darwin.go b/internal/common/common_darwin.go
index b236da1..2b6d4c1 100644
--- a/internal/common/common_darwin.go
+++ b/internal/common/common_darwin.go
@@ -12,16 +12,13 @@ import (
 )
 
 func DoSysctrl(mib string) ([]string, error) {
-	err := os.Setenv("LC_ALL", "C")
-	if err != nil {
-		return []string{}, err
-	}
-
 	sysctl, err := exec.LookPath("/usr/sbin/sysctl")
 	if err != nil {
 		return []string{}, err
 	}
-	out, err := exec.Command(sysctl, "-n", mib).Output()
+	cmd := exec.Command(sysctl, "-n", mib)
+	cmd.Env = getSysctrlEnv(os.Environ())
+	out, err := cmd.Output()
 	if err != nil {
 		return []string{}, err
 	}
diff --git a/internal/common/common_freebsd.go b/internal/common/common_freebsd.go
index 668bdc4..107e2c9 100644
--- a/internal/common/common_freebsd.go
+++ b/internal/common/common_freebsd.go
@@ -12,15 +12,13 @@ import (
 )
 
 func DoSysctrl(mib string) ([]string, error) {
-	err := os.Setenv("LC_ALL", "C")
-	if err != nil {
-		return []string{}, err
-	}
 	sysctl, err := exec.LookPath("/sbin/sysctl")
 	if err != nil {
 		return []string{}, err
 	}
-	out, err := exec.Command(sysctl, "-n", mib).Output()
+	cmd := exec.Command(sysctl, "-n", mib)
+	cmd.Env = getSysctrlEnv(os.Environ())
+	out, err := cmd.Output()
 	if err != nil {
 		return []string{}, err
 	}
diff --git a/internal/common/common_linux.go b/internal/common/common_linux.go
index 5347b60..4e829e0 100644
--- a/internal/common/common_linux.go
+++ b/internal/common/common_linux.go
@@ -9,23 +9,12 @@ import (
 )
 
 func DoSysctrl(mib string) ([]string, error) {
-	hostEnv := os.Environ()
-	foundLC := false
-	for i, line := range hostEnv {
-		if strings.HasPrefix(line, "LC_ALL") {
-			hostEnv[i] = "LC_ALL=C"
-			foundLC = true
-		}
-	}
-	if !foundLC {
-		hostEnv = append(hostEnv, "LC_ALL=C")
-	}
 	sysctl, err := exec.LookPath("/sbin/sysctl")
 	if err != nil {
 		return []string{}, err
 	}
 	cmd := exec.Command(sysctl, "-n", mib)
-	cmd.Env = hostEnv
+	cmd.Env = getSysctrlEnv(os.Environ())
 	out, err := cmd.Output()
 	if err != nil {
 		return []string{}, err
diff --git a/internal/common/common_openbsd.go b/internal/common/common_openbsd.go
index 8625e1f..398f785 100644
--- a/internal/common/common_openbsd.go
+++ b/internal/common/common_openbsd.go
@@ -12,15 +12,13 @@ import (
 )
 
 func DoSysctrl(mib string) ([]string, error) {
-	err := os.Setenv("LC_ALL", "C")
-	if err != nil {
-		return []string{}, err
-	}
 	sysctl, err := exec.LookPath("/sbin/sysctl")
 	if err != nil {
 		return []string{}, err
 	}
-	out, err := exec.Command(sysctl, "-n", mib).Output()
+	cmd := exec.Command(sysctl, "-n", mib)
+	cmd.Env = getSysctrlEnv(os.Environ())
+	out, err := cmd.Output()
 	if err != nil {
 		return []string{}, err
 	}
diff --git a/internal/common/common_test.go b/internal/common/common_test.go
index b7bda8b..3b05d53 100644
--- a/internal/common/common_test.go
+++ b/internal/common/common_test.go
@@ -2,6 +2,8 @@ package common
 
 import (
 	"fmt"
+	"os"
+	"reflect"
 	"strings"
 	"testing"
 )
@@ -95,3 +97,33 @@ func TestHostEtc(t *testing.T) {
 		t.Errorf("invalid HostEtc, %s", p)
 	}
 }
+
+func TestGetSysctrlEnv(t *testing.T) {
+	// Append case
+	env := getSysctrlEnv([]string{"FOO=bar"})
+	if !reflect.DeepEqual(env, []string{"FOO=bar", "LC_ALL=C"}) {
+		t.Errorf("unexpected append result from getSysctrlEnv: %q", env)
+	}
+
+	// Replace case
+	env = getSysctrlEnv([]string{"FOO=bar", "LC_ALL=en_US.UTF-8"})
+	if !reflect.DeepEqual(env, []string{"FOO=bar", "LC_ALL=C"}) {
+		t.Errorf("unexpected replace result from getSysctrlEnv: %q", env)
+	}
+
+	// Test against real env
+	env = getSysctrlEnv(os.Environ())
+	found := false
+	for _, v := range env {
+		if v == "LC_ALL=C" {
+			found = true
+			continue
+		}
+		if strings.HasPrefix(v, "LC_ALL") {
+			t.Fatalf("unexpected LC_ALL value: %q", v)
+		}
+	}
+	if !found {
+		t.Errorf("unexpected real result from getSysctrlEnv: %q", env)
+	}
+}