--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/cmds/multipass-checkpassword/checkpassword.go	Fri Oct 30 00:18:13 2015 -0400
@@ -0,0 +1,49 @@
+package main
+
+import (
+	"bufio"
+	"os"
+	"os/user"
+	"syscall"
+
+	"pfish.zone/go/multipass/file"
+)
+
+const (
+	InternalError = 111
+	Failed        = 1
+)
+
+func main() {
+	infile := os.NewFile(3, "")
+	reader := bufio.NewReader(infile)
+	username, err := reader.ReadString(0)
+	if err != nil {
+		os.Exit(InternalError)
+	}
+	username = username[:len(username)-1]
+	pass, err := reader.ReadString(0)
+	if err != nil {
+		os.Exit(InternalError)
+	}
+	pass = pass[:len(pass)-1]
+	infile.Close()
+	passfile, err := file.ForUser(username)
+	if err != nil {
+		os.Exit(Failed)
+	}
+	success, _ := passfile.Authenticate(pass)
+	if !success {
+		os.Exit(Failed)
+	}
+	user, err := user.Lookup(username)
+	if err != nil {
+		os.Exit(Failed)
+	}
+	os.Setenv("USER", user.Username)
+	os.Setenv("HOME", user.HomeDir)
+	os.Setenv("userdb_uid", user.Uid)
+	os.Setenv("userdb_gid", user.Gid)
+	os.Setenv("EXTRA", "userdb_uid userdb_gid")
+	syscall.Exec(os.Args[1], os.Args[1:], os.Environ())
+}