Add osinfo library (#210)

osinfo/osinfo.go

@@ -0,0 +1,20 @@
+/*
+Copyright 2017 Google Inc. All Rights Reserved.
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+    http://www.apache.org/licenses/LICENSE-2.0
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// Package osinfo provides basic system info functions for Windows and
+// Linux.
+package osinfo
+
+type DistributionInfo struct {
+	LongName, ShortName, Version, Kernel string
+}

osinfo/osinfo_linux.go

@@ -0,0 +1,122 @@
+/*
+Copyright 2017 Google Inc. All Rights Reserved.
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+    http://www.apache.org/licenses/LICENSE-2.0
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package osinfo
+
+import (
+	"bufio"
+	"bytes"
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"os/exec"
+	"regexp"
+	"strings"
+)
+
+var (
+	entRelVerRgx = regexp.MustCompile(`/d+(\./d+)?(\./d+)?`)
+)
+
+const (
+	osRelease = "/etc/os-release"
+	oRelease  = "/etc/oracle-release"
+	rhRelease = "/etc/redhat-release"
+)
+
+func exists(name string) bool {
+	if _, err := os.Stat(name); os.IsNotExist(err) {
+		return false
+	}
+	return true
+}
+
+func parseOsRelease(path string) (*DistributionInfo, error) {
+	di := &DistributionInfo{ShortName: "linux"}
+	b, err := ioutil.ReadFile(path)
+	if err != nil {
+		return di, fmt.Errorf("unable to obtain release info: %v", err)
+	}
+
+	scanner := bufio.NewScanner(bytes.NewReader(b))
+	for scanner.Scan() {
+		entry := strings.Split(scanner.Text(), "=")
+		switch entry[0] {
+		case "":
+			continue
+		case "PRETTY_NAME":
+			di.LongName = strings.Trim(entry[1], `"`)
+		case "VERSION_ID":
+			di.Version = strings.Trim(entry[1], `"`)
+		case "ID":
+			di.ShortName = strings.Trim(entry[1], `"`)
+		}
+		if di.LongName != "" && di.Version != "" && di.ShortName != "" {
+			break
+		}
+	}
+
+	return di, nil
+}
+
+func parseEnterpriseRelease(path string) (*DistributionInfo, error) {
+	b, err := ioutil.ReadFile(path)
+	if err != nil {
+		return &DistributionInfo{ShortName: "linux"}, fmt.Errorf("unable to obtain release info: %v", err)
+	}
+	rel := string(b)
+
+	var sn string
+	switch {
+	case strings.Contains(rel, "CentOS"):
+		sn = "centos"
+	case strings.Contains(rel, "Red Hat"):
+		sn = "rhel"
+	case strings.Contains(rel, "Oracle"):
+		sn = "ol"
+	}
+
+	return &DistributionInfo{
+		ShortName: sn,
+		LongName:  strings.Replace(rel, " release ", " ", 1),
+		Version:   entRelVerRgx.FindString(rel),
+	}, nil
+}
+
+// GetDistributionInfo reports DistributionInfo.
+func GetDistributionInfo() (*DistributionInfo, error) {
+	var di *DistributionInfo
+	var err error
+	switch {
+	// Check for /etc/os-release first.
+	case exists(osRelease):
+		di, err = parseOsRelease(osRelease)
+	case exists(oRelease):
+		di, err = parseEnterpriseRelease(oRelease)
+	case exists(rhRelease):
+		di, err = parseEnterpriseRelease(rhRelease)
+	default:
+		err = errors.New("unable to obtain release info, no known /etc/*-release exists")
+	}
+	if err != nil {
+		return nil, err
+	}
+
+	out, err := exec.Command("/bin/uname", "-r").CombinedOutput()
+	if err != nil {
+		return nil, err
+	}
+	di.Kernel = strings.TrimSpace(string(out))
+	return di, nil
+}

osinfo/osinfo_windows.go

@@ -0,0 +1,41 @@
+/*
+Copyright 2017 Google Inc. All Rights Reserved.
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+    http://www.apache.org/licenses/LICENSE-2.0
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package osinfo
+
+import (
+	"github.com/StackExchange/wmi"
+)
+
+// GetDistributionInfo reports DistributionInfo.
+func GetDistributionInfo() (*DistributionInfo, error) {
+	oi, err := osInfo()
+	if err != nil {
+		return nil, err
+	}
+
+	// TODO(ajackura): Get kernel version from ntoskrnl.exe.
+	return &DistributionInfo{ShortName: "windows", LongName: oi.Caption, Version: oi.Version, kernel: oi.Version}, nil
+}
+
+type win32_OperatingSystem struct {
+	Caption, Version string
+}
+
+func osInfo() (*win32_OperatingSystem, error) {
+	var ops []win32_OperatingSystem
+	if err := wmi.Query(wmi.CreateQuery(&ops, ""), &ops); err != nil {
+		return nil, err
+	}
+	return &ops[0], nil
+}