check version for docker-default aa profile

Signed-off-by: Jessica Frazelle <acidburn@docker.com>

aaparser/aaparser.go

@@ -0,0 +1,45 @@
+package aaparser
+
+import (
+	"fmt"
+	"log"
+	"os/exec"
+	"strconv"
+	"strings"
+)
+
+// GetVersion returns the major and minor version of apparmor_parser
+func GetVersion() (int, int, error) {
+	// get the apparmor_version version
+	cmd := exec.Command("apparmor_parser", "--version")
+
+	output, err := cmd.CombinedOutput()
+	if err != nil {
+		log.Fatalf("getting apparmor_parser version failed: %s (%s)", err, output)
+	}
+
+	// parse the version from the output
+	// output is in the form of the following:
+	// AppArmor parser version 2.9.1
+	// Copyright (C) 1999-2008 Novell Inc.
+	// Copyright 2009-2012 Canonical Ltd.
+	lines := strings.SplitN(string(output), "\n", 2)
+	words := strings.Split(lines[0], " ")
+	version := words[len(words)-1]
+	// split by major minor version
+	v := strings.Split(version, ".")
+	if len(v) < 2 {
+		return -1, -1, fmt.Errorf("parsing major minor version failed for %q", version)
+	}
+
+	majorVersion, err := strconv.Atoi(v[0])
+	if err != nil {
+		return -1, -1, err
+	}
+	minorVersion, err := strconv.Atoi(v[1])
+	if err != nil {
+		return -1, -1, err
+	}
+
+	return majorVersion, minorVersion, nil
+}