...G...... [ZBX-20030] fixed system.cpu.num runtime cpu change in Zabbix agent 2

* commit '1bd747756705f228be7dab888be3c198d9414a64':
  ...G...... [ZBX-20030] code clean up
  .......... [ZBX-20030] fixed linux discovery
  .......... [ZBX-20030] aded change-log
  ...G...... [ZBX-20030] code clean up
  ...G...... [ZBX-20030] code clean up
  ...G...... [ZBX-20030] fixed system.cpu.num runtime cpu change count for windows in Zabbix agent 2
  ...G...... [ZBX-20030] fixed system.cpu.num runtime cpu change count for linux in Zabbix agent 2

(cherry picked from commit c2dfb47315478463670b65e7a2b9af1fc3f3dcec)

4 files changed, 177 insertions, 15 deletions

diff --git a/src/go/plugins/system/cpu/cpu.go b/src/go/plugins/system/cpu/cpu.go
index e2eb6e9e86c..5f22df69edf 100644
--- a/src/go/plugins/system/cpu/cpu.go
+++ b/src/go/plugins/system/cpu/cpu.go
@@ -23,6 +23,8 @@ import (
 	"encoding/json"
 	"errors"
 	"strconv"
+
+	"zabbix.com/pkg/zbxerr"
 )
 
 const pluginName = "Cpu"
@@ -101,29 +103,21 @@ func (p *Plugin) getCpuDiscovery(params []string) (result interface{}, err error
 }
 
 func (p *Plugin) getCpuNum(params []string) (result interface{}, err error) {
-	mask := cpuStatusOnline
 	switch len(params) {
 	case 1:
 		switch params[0] {
 		case "", "online":
-			// default value, already initialized
+			return numCPUOnline(), nil
 		case "max":
-			mask = cpuStatusOnline | cpuStatusOffline
+			return numCPUConf(), nil
 		default:
 			return nil, errors.New("Invalid first parameter.")
 		}
 	case 0:
+		return numCPUOnline(), nil
 	default:
-		return nil, errors.New("Too many parameters.")
-	}
-
-	var num int
-	for i := 1; i < len(p.cpus); i++ {
-		if p.cpus[i].status&mask != 0 {
-			num++
-		}
+		return nil, zbxerr.ErrorTooManyParameters
 	}
-	return num, nil
 }
 
 func periodByMode(mode string) (period historyIndex) {
diff --git a/src/go/plugins/system/cpu/cpu_linux.go b/src/go/plugins/system/cpu/cpu_linux.go
index e9eb21e8695..d52fff06fd4 100644
--- a/src/go/plugins/system/cpu/cpu_linux.go
+++ b/src/go/plugins/system/cpu/cpu_linux.go
@@ -77,11 +77,14 @@ func (p *Plugin) Collect() (err error) {
 			if i, err = strconv.ParseInt(fields[0][3:], 10, 32); err != nil {
 				return
 			}
-			if index = int(i); index < 0 || index+1 >= len(p.cpus) {
+
+			if index = int(i); index < 0 {
 				p.Debugf("invalid CPU index %d", index)
 				continue
 			}
 
+			p.addCpu(index)
+
 			status = cpuStatusOnline
 		} else {
 			index = -1
@@ -112,12 +115,32 @@ func (p *Plugin) Collect() (err error) {
 	return nil
 }
 
-func numCPU() int {
+func (p *Plugin) addCpu(index int) {
+	if p == nil || p.cpus == nil {
+		return
+	}
+
+	if index == 0 {
+		return
+	}
+
+	if index+1 >= len(p.cpus) {
+		for idx := p.cpus[len(p.cpus)-1].index; idx < index; idx++ {
+			p.cpus = append(p.cpus, &cpuUnit{index: idx + 1, status: cpuStatusOffline})
+		}
+	}
+}
+
+func numCPUConf() int {
 	return int(C.sysconf(C._SC_NPROCESSORS_CONF))
 }
 
+func numCPUOnline() int {
+	return int(C.sysconf(C._SC_NPROCESSORS_ONLN))
+}
+
 func (p *Plugin) Start() {
-	p.cpus = p.newCpus(numCPU())
+	p.cpus = p.newCpus(numCPUConf())
 }
 
 func (p *Plugin) Stop() {
diff --git a/src/go/plugins/system/cpu/cpu_linux_test.go b/src/go/plugins/system/cpu/cpu_linux_test.go
new file mode 100644
index 00000000000..87d719352ca
--- /dev/null
+++ b/src/go/plugins/system/cpu/cpu_linux_test.go
@@ -0,0 +1,136 @@
+/*
+** Zabbix
+** Copyright (C) 2001-2022 Zabbix SIA
+**
+** This program is free software; you can redistribute it and/or modify
+** it under the terms of the GNU General Public License as published by
+** the Free Software Foundation; either version 2 of the License, or
+** (at your option) any later version.
+**
+** This program is distributed in the hope that it will be useful,
+** but WITHOUT ANY WARRANTY; without even the implied warranty of
+** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+** GNU General Public License for more details.
+**
+** You should have received a copy of the GNU General Public License
+** along with this program; if not, write to the Free Software
+** Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+**/
+
+package cpu
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestPlugin_addCpu(t *testing.T) {
+	type fields struct {
+		cpus []*cpuUnit
+	}
+	type args struct {
+		index int
+	}
+	tests := []struct {
+		name   string
+		fields fields
+		args   args
+		want   []*cpuUnit
+	}{
+		{
+			"one_offline_cpu",
+			fields{
+				[]*cpuUnit{
+					{index: -1, status: cpuStatusOffline},
+					{index: 0, status: cpuStatusOffline},
+					{index: 1, status: cpuStatusOffline},
+				},
+			},
+			args{2},
+			[]*cpuUnit{
+				{index: -1, status: cpuStatusOffline},
+				{index: 0, status: cpuStatusOffline},
+				{index: 1, status: cpuStatusOffline},
+				{index: 2, status: cpuStatusOffline},
+			},
+		},
+		{
+			"two_offline_cpu",
+			fields{
+				[]*cpuUnit{
+					{index: -1, status: cpuStatusOffline},
+					{index: 0, status: cpuStatusOffline},
+					{index: 1, status: cpuStatusOffline},
+				},
+			},
+			args{3},
+			[]*cpuUnit{
+				{index: -1, status: cpuStatusOffline},
+				{index: 0, status: cpuStatusOffline},
+				{index: 1, status: cpuStatusOffline},
+				{index: 2, status: cpuStatusOffline},
+				{index: 3, status: cpuStatusOffline},
+			},
+		},
+		{
+			"ten_offline_cpu",
+			fields{
+				[]*cpuUnit{
+					{index: -1, status: cpuStatusOffline},
+					{index: 0, status: cpuStatusOffline},
+					{index: 1, status: cpuStatusOffline},
+				},
+			},
+			args{11},
+			[]*cpuUnit{
+				{index: -1, status: cpuStatusOffline},
+				{index: 0, status: cpuStatusOffline},
+				{index: 1, status: cpuStatusOffline},
+				{index: 2, status: cpuStatusOffline},
+				{index: 3, status: cpuStatusOffline},
+				{index: 4, status: cpuStatusOffline},
+				{index: 5, status: cpuStatusOffline},
+				{index: 6, status: cpuStatusOffline},
+				{index: 7, status: cpuStatusOffline},
+				{index: 8, status: cpuStatusOffline},
+				{index: 9, status: cpuStatusOffline},
+				{index: 10, status: cpuStatusOffline},
+				{index: 11, status: cpuStatusOffline},
+			},
+		},
+		{
+			"no_offline_cpu",
+			fields{
+				[]*cpuUnit{
+					{index: -1, status: cpuStatusOffline},
+					{index: 0, status: cpuStatusOffline},
+					{index: 1, status: cpuStatusOffline},
+				},
+			},
+			args{1},
+			[]*cpuUnit{
+				{index: -1, status: cpuStatusOffline},
+				{index: 0, status: cpuStatusOffline},
+				{index: 1, status: cpuStatusOffline},
+			},
+		},
+		{
+			"empty", fields{[]*cpuUnit{}}, args{}, []*cpuUnit{},
+		},
+		{
+			"nil", fields{nil}, args{}, nil,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			p := &Plugin{
+				cpus: tt.fields.cpus,
+			}
+			p.addCpu(tt.args.index)
+
+			if !reflect.DeepEqual(p.cpus, tt.want) {
+				t.Errorf("addCpu() got = %v, want %v", p.cpus, tt.want)
+			}
+		})
+	}
+}
diff --git a/src/go/plugins/system/cpu/cpu_windows.go b/src/go/plugins/system/cpu/cpu_windows.go
index 0b175a17dfe..eff02894286 100644
--- a/src/go/plugins/system/cpu/cpu_windows.go
+++ b/src/go/plugins/system/cpu/cpu_windows.go
@@ -43,6 +43,15 @@ const (
 	defaultIndex = 60
 )
 
+func numCPUOnline() int {
+	return numCPU()
+}
+
+func numCPUConf() int {
+	// unsupported on Windows
+	return 0
+}
+
 func numCPU() (numCpu int) {
 	size, err := win32.GetLogicalProcessorInformationEx(win32.RelationProcessorCore, nil)
 	if err != nil {