host: Add Solaris support for Info, {Boot,Up}time

This commit adds support for Info(), BootTime() and Uptime() in package
Host. It uses no cgo, preferring to parse the output of `kstat -p`
instead.

Thanks go to @gfrey for the parsing logic for `/etc/release` and `uname`.

host/host_fallback.go

@@ -1,4 +1,4 @@
-// +build !darwin,!linux,!freebsd,!openbsd,!windows
+// +build !darwin,!linux,!freebsd,!openbsd,!solaris,!windows
 
 package host
 

host/host_solaris.go

@@ -0,0 +1,132 @@
+package host
+
+import (
+	"bufio"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"os/exec"
+	"regexp"
+	"runtime"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/shirou/gopsutil/internal/common"
+)
+
+func Info() (*InfoStat, error) {
+	result := &InfoStat{
+		OS: runtime.GOOS,
+	}
+
+	hostname, err := os.Hostname()
+	if err != nil {
+		return nil, err
+	}
+	result.Hostname = hostname
+
+	// Parse versions from output of `uname(1)`
+	uname, err := exec.LookPath("/usr/bin/uname")
+	if err != nil {
+		return nil, err
+	}
+
+	out, err := invoke.Command(uname, "-srv")
+	if err != nil {
+		return nil, err
+	}
+
+	fields := strings.Fields(string(out))
+	if len(fields) >= 1 {
+		result.PlatformFamily = fields[0]
+	}
+	if len(fields) >= 2 {
+		result.KernelVersion = fields[1]
+	}
+	if len(fields) == 3 {
+		result.PlatformVersion = fields[2]
+	}
+
+	// Find distribution name from /etc/release
+	fh, err := os.Open("/etc/release")
+	if err != nil {
+		return nil, err
+	}
+	defer fh.Close()
+
+	sc := bufio.NewScanner(fh)
+	if sc.Scan() {
+		line := strings.TrimSpace(sc.Text())
+		switch {
+		case strings.HasPrefix(line, "SmartOS"):
+			result.Platform = "SmartOS"
+		case strings.HasPrefix(line, "OpenIndiana"):
+			result.Platform = "OpenIndiana"
+		case strings.HasPrefix(line, "OmniOS"):
+			result.Platform = "OmniOS"
+		case strings.HasPrefix(line, "Open Storage"):
+			result.Platform = "NexentaStor"
+		case strings.HasPrefix(line, "Solaris"):
+			result.Platform = "Solaris"
+		case strings.HasPrefix(line, "Oracle Solaris"):
+			result.Platform = "Solaris"
+		default:
+			result.Platform = strings.Fields(line)[0]
+		}
+	}
+
+	// Find the boot time and calculate uptime relative to it
+	bootTime, err := BootTime()
+	if err != nil {
+		return nil, err
+	}
+	result.BootTime = bootTime
+	result.Uptime = uptimeSince(bootTime)
+
+	// Count number of processes based on the number of entries in /proc
+	dirs, err := ioutil.ReadDir("/proc")
+	if err != nil {
+		return nil, err
+	}
+	result.Procs = uint64(len(dirs))
+
+	return result, nil
+}
+
+var kstatMatch = regexp.MustCompile(`([^\s]+)[\s]+([^\s]*)`)
+
+func BootTime() (uint64, error) {
+	kstat, err := exec.LookPath("/usr/bin/kstat")
+	if err != nil {
+		return 0, err
+	}
+
+	out, err := invoke.Command(kstat, "-p", "unix:0:system_misc:boot_time")
+	if err != nil {
+		return 0, err
+	}
+
+	kstats := kstatMatch.FindAllStringSubmatch(string(out), -1)
+	if len(kstats) != 1 {
+		return 0, fmt.Errorf("Expected 1 kstat, found %d", len(kstats))
+	}
+
+	return strconv.ParseUint(kstats[0][2], 10, 64)
+}
+
+func Uptime() (uint64, error) {
+	bootTime, err := BootTime()
+	if err != nil {
+		return 0, err
+	}
+	return uptimeSince(bootTime), nil
+}
+
+func uptimeSince(since uint64) uint64 {
+	return uint64(time.Now().Unix()) - since
+}
+
+func Users() ([]UserStat, error) {
+	return []UserStat{}, common.ErrNotImplementedError
+}