Revert "Remove pledge(2) support"

This reverts commit bc3215a8a6.

dnscrypt-proxy/config.go

@@ -193,6 +193,9 @@ func ConfigLoad(proxy *Proxy, svcFlag *string) error {
 
 	flag.Parse()
 
+	if *child {
+		PledgeChild()
+	}
 	if *svcFlag == "stop" || *svcFlag == "uninstall" {
 		return nil
 	}

dnscrypt-proxy/main.go

@@ -25,6 +25,8 @@ type App struct {
 func main() {
 	dlog.Init("dnscrypt-proxy", dlog.SeverityNotice, "DAEMON")
 
+	Pledge()
+
 	pwd, err := os.Getwd()
 	if err != nil {
 		dlog.Fatal("Unable to find the path to the current directory")

dnscrypt-proxy/pledge_openbsd.go

@@ -0,0 +1,15 @@
+// +build openbsd
+
+package main
+
+import (
+	"golang.org/x/sys/unix"
+)
+
+func Pledge() {
+	unix.Pledge("stdio rpath wpath cpath tmppath inet fattr flock dns getpw sendfd recvfd proc exec id", nil)
+}
+
+func PledgeChild() {
+	unix.Pledge("stdio rpath wpath cpath tmppath inet fattr flock dns recvfd", nil)
+}

dnscrypt-proxy/pledge_others.go

@@ -0,0 +1,11 @@
+// +build !openbsd
+
+package main
+
+func Pledge() {
+
+}
+
+func PledgeChild() {
+
+}