added generic user lookup and foreground processes

lookup_nocgo.go

@@ -0,0 +1,43 @@
+// Copyright (C) 2017 Marius Schellenberger
+
+// +build darwin dragonfly freebsd android linux netbsd openbsd solaris
+// +build !cgo
+
+package godrop
+
+import (
+	"io/ioutil"
+	"os"
+	"regexp"
+)
+
+func readFile(name, file string) (id string, err error) {
+	id = "-1"
+	if name == "" {
+		return
+	}
+	f, err := os.Open(file)
+	if err != nil {
+		return
+	}
+	b, err := ioutil.ReadAll(f)
+	if err != nil {
+		return
+	}
+	r := regexp.MustCompile(name + ":.*:(\\d+)")
+	m := r.FindAllStringSubmatch(string(b), 1)
+	if len(m) == 1 {
+		if len(m[0]) == 2 {
+			return m[0][1], nil
+		}
+	}
+	return
+}
+
+func lookupUID(username string) (string, error) {
+	return readFile(username, "/etc/passwd")
+}
+
+func lookupGID(name string) (string, error) {
+	return readFile(name, "/etc/group")
+}