Merge pull request #43 from DataDog/kserrania/fix-cpu-m1

[macOS M1] Backports from upstream to fix cpu.Info() crashes

Since #40, we can build projects containing this gopsutil fork on macOS M1.

However, using cpu.Info() causes a crash: sysctl hw.cpufrequency doesn't return anything on M1, which makes the following snippet crash:

out, err = invoke.Command(sysctl, "hw.cpufrequency")
	if err != nil {
		return ret, err
	}

	values := strings.Fields(string(out))
	hz, err := strconv.ParseFloat(values[1], 64)
with an index out-of-range error.

This PR:
- backports Lomanic/gopsutil@2ec3560, which uses golang.org/x/sys/unix.Sysctl instead of manual calls to the sysctl binary, preventing the crash
- backports shirou#1192 to not make cpu.Info() return an error when the CPU frequency cannot be found, to prevent the method from erroring on M1.

Author: KSerrania

cpu/cpu_darwin.go

@@ -3,9 +3,10 @@
 package cpu
 
 import (
-	"os/exec"
 	"strconv"
 	"strings"
+
+	"golang.org/x/sys/unix"
 )
 
 // sys/resource.h
@@ -32,75 +33,45 @@ func Times(percpu bool) ([]TimesStat, error) {
 // Returns only one CPUInfoStat on FreeBSD
 func Info() ([]InfoStat, error) {
 	var ret []InfoStat
-	sysctl, err := exec.LookPath("/usr/sbin/sysctl")
-	if err != nil {
-		return ret, err
-	}
-	out, err := invoke.Command(sysctl, "machdep.cpu")
-	if err != nil {
-		return ret, err
-	}
 
 	c := InfoStat{}
-	for _, line := range strings.Split(string(out), "\n") {
-		values := strings.Fields(line)
-		if len(values) < 1 {
-			continue
+	c.ModelName, _ = unix.Sysctl("machdep.cpu.brand_string")
+	family, _ := unix.SysctlUint32("machdep.cpu.family")
+	c.Family = strconv.FormatUint(uint64(family), 10)
+	model, _ := unix.SysctlUint32("machdep.cpu.model")
+	c.Model = strconv.FormatUint(uint64(model), 10)
+	stepping, _ := unix.SysctlUint32("machdep.cpu.stepping")
+	c.Stepping = int32(stepping)
+	features, err := unix.Sysctl("machdep.cpu.features")
+	if err == nil {
+		for _, v := range strings.Fields(features) {
+			c.Flags = append(c.Flags, strings.ToLower(v))
 		}
-
-		t, err := strconv.ParseInt(values[1], 10, 64)
-		// err is not checked here because some value is string.
-		if strings.HasPrefix(line, "machdep.cpu.brand_string") {
-			c.ModelName = strings.Join(values[1:], " ")
-		} else if strings.HasPrefix(line, "machdep.cpu.family") {
-			c.Family = values[1]
-		} else if strings.HasPrefix(line, "machdep.cpu.model") {
-			c.Model = values[1]
-		} else if strings.HasPrefix(line, "machdep.cpu.stepping") {
-			if err != nil {
-				return ret, err
-			}
-			c.Stepping = int32(t)
-		} else if strings.HasPrefix(line, "machdep.cpu.features") {
-			for _, v := range values[1:] {
-				c.Flags = append(c.Flags, strings.ToLower(v))
-			}
-		} else if strings.HasPrefix(line, "machdep.cpu.leaf7_features") {
-			for _, v := range values[1:] {
-				c.Flags = append(c.Flags, strings.ToLower(v))
-			}
-		} else if strings.HasPrefix(line, "machdep.cpu.extfeatures") {
-			for _, v := range values[1:] {
-				c.Flags = append(c.Flags, strings.ToLower(v))
-			}
-		} else if strings.HasPrefix(line, "machdep.cpu.core_count") {
-			if err != nil {
-				return ret, err
-			}
-			c.Cores = int32(t)
-		} else if strings.HasPrefix(line, "machdep.cpu.cache.size") {
-			if err != nil {
-				return ret, err
-			}
-			c.CacheSize = int32(t)
-		} else if strings.HasPrefix(line, "machdep.cpu.vendor") {
-			c.VendorID = values[1]
+	}
+	leaf7Features, err := unix.Sysctl("machdep.cpu.leaf7_features")
+	if err == nil {
+		for _, v := range strings.Fields(leaf7Features) {
+			c.Flags = append(c.Flags, strings.ToLower(v))
 		}
 	}
+	extfeatures, err := unix.Sysctl("machdep.cpu.extfeatures")
+	if err == nil {
+		for _, v := range strings.Fields(extfeatures) {
+			c.Flags = append(c.Flags, strings.ToLower(v))
+		}
+	}
+	cores, _ := unix.SysctlUint32("machdep.cpu.core_count")
+	c.Cores = int32(cores)
+	cacheSize, _ := unix.SysctlUint32("machdep.cpu.cache.size")
+	c.CacheSize = int32(cacheSize)
+	c.VendorID, _ = unix.Sysctl("machdep.cpu.vendor")
 
 	// Use the rated frequency of the CPU. This is a static value and does not
 	// account for low power or Turbo Boost modes.
-	out, err = invoke.Command(sysctl, "hw.cpufrequency")
-	if err != nil {
-		return ret, err
-	}
-
-	values := strings.Fields(string(out))
-	hz, err := strconv.ParseFloat(values[1], 64)
-	if err != nil {
-		return ret, err
+	cpuFrequency, err := unix.SysctlUint64("hw.cpufrequency")
+	if err == nil {
+		c.Mhz = float64(cpuFrequency) / 1000000.0
 	}
-	c.Mhz = hz / 1000000.0
 
 	return append(ret, c), nil
 }