Replace use of cgo for getting number of online CPUs

container/libcontainer/handler.go

@@ -27,18 +27,15 @@ import (
 
 	"github.com/google/cadvisor/container"
 	info "github.com/google/cadvisor/info/v1"
+	"golang.org/x/sys/unix"
 
 	"bytes"
+
 	"github.com/opencontainers/runc/libcontainer"
 	"github.com/opencontainers/runc/libcontainer/cgroups"
 	"k8s.io/klog"
 )
 
-/*
-#include <unistd.h>
-*/
-import "C"
-
 type Handler struct {
 	cgroupManager   cgroups.Manager
 	rootFs          string
@@ -514,19 +511,12 @@ func setCpuStats(s *cgroups.Stats, ret *info.ContainerStats, withPerCPU bool) {
 
 }
 
-// Copied from
-// https://github.com/moby/moby/blob/8b1adf55c2af329a4334f21d9444d6a169000c81/daemon/stats/collector_unix.go#L73
-// Apache 2.0, Copyright Docker, Inc.
 func getNumberOnlineCPUs() (uint32, error) {
-	i, err := C.sysconf(C._SC_NPROCESSORS_ONLN)
-	// According to POSIX - errno is undefined after successful
-	// sysconf, and can be non-zero in several cases, so look for
-	// error in returned value not in errno.
-	// (https://sourceware.org/bugzilla/show_bug.cgi?id=21536)
-	if i == -1 {
+	var availableCPUs unix.CPUSet
+	if err := unix.SchedGetaffinity(0, &availableCPUs); err != nil {
 		return 0, err
 	}
-	return uint32(i), nil
+	return uint32(availableCPUs.Count()), nil
 }
 
 func setDiskIoStats(s *cgroups.Stats, ret *info.ContainerStats) {