add code for retrieving kernel modules

pkg/util/metrics/system/common.go

@@ -0,0 +1,38 @@
+/*
+Copyright 2020 The Kubernetes Authors 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 system
+
+import (
+	"bufio"
+	"os"
+)
+
+// ReadFile reads contents from a file and returns lines.
+func ReadFile(filename string) ([]string, error) {
+	file, err := os.Open(filename)
+	if err != nil {
+		return nil, err
+	}
+	defer file.Close()
+
+	var result []string
+	s := bufio.NewScanner(file)
+	for s.Scan() {
+		result = append(result, s.Text())
+	}
+	if s.Err() != nil {
+		return nil, err
+	}
+	return result, nil
+}

pkg/util/metrics/system/module_stats.go

@@ -0,0 +1,85 @@
+/*
+Copyright 2020 The Kubernetes Authors 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 system
+
+import (
+	"encoding/json"
+	"fmt"
+	"strconv"
+	"strings"
+)
+
+type ModuleStat struct {
+	ModuleName  string `json:"moduleName"`
+	Instances   uint64 `json:"instances"`
+	Proprietary bool   `json:"proprietary"`
+	OutOfTree   bool   `json:"outOfTree"`
+	Unsigned    bool   `json:"unsigned"`
+}
+
+func (d ModuleStat) String() string {
+	s, _ := json.Marshal(d)
+	return string(s)
+}
+
+// Module returns all the kernel modules and their
+// usage. It is read from cat /proc/modules.
+func Modules() ([]ModuleStat, error) {
+	filename := "/proc/modules"
+	lines, err := ReadFile(filename)
+	if err != nil {
+		return nil, fmt.Errorf("Error reading the contents of %s: %s", filename, err)
+	}
+	var result = make([]ModuleStat, 0, len(lines))
+
+	/* a line of /proc/modules has the following structure
+	  nf_nat 61440 2 xt_MASQUERADE,iptable_nat, Live 0x0000000000000000  (O)
+	  (1)		(2)  (3)    (4)										 (5)	 	(6)								(7)
+		(1)  name of the module
+		(2)	 memory size of the module, in bytes
+		(3)  instances of the module are currently loaded
+		(4)  module dependencies
+		(5)  load state of the module: live, loading or unloading
+		(6)  memory offset for the loaded module.
+		(7)  return a string to represent the kernel taint state. (used here: "P" - Proprietary, "O" - out of tree kernel module, "E" - unsigned module
+	*/
+	for _, line := range lines {
+		fields := strings.Fields(line)
+		moduleName := fields[0] // name of the module
+		numberOfInstances, err :=
+			strconv.ParseUint((fields[1]), 10, 64) // instances of the module are currently loaded
+		if err != nil {
+			return nil, err
+		}
+
+		var isProprietary = false
+		var isOutofTree = false
+		var isUnsigned = false
+		// if the len of the fields is greater than 6, then the kernel taint state is available.
+		if len(fields) > 6 {
+			isProprietary = strings.Contains(fields[6], "P")
+			isOutofTree = strings.Contains(fields[6], "O")
+			isUnsigned = strings.Contains(fields[6], "E")
+		}
+		var stats = ModuleStat{
+			ModuleName:  moduleName,
+			Instances:   numberOfInstances,
+			Proprietary: isProprietary,
+			OutOfTree:   isOutofTree,
+			Unsigned:    isUnsigned,
+		}
+		result = append(result, stats)
+	}
+	return result, nil
+}

pkg/util/metrics/system/module_stats_test.go

@@ -0,0 +1,44 @@
+/*
+Copyright 2019 The Kubernetes Authors 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 system
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestModules(t *testing.T) {
+	modules, err := Modules()
+	if err != nil {
+		t.Errorf("error %v", err)
+	}
+	if modules == nil {
+		t.Error("Error retrieving modules")
+	}
+}
+
+func TestModuleStat_String(t *testing.T) {
+	v := ModuleStat{
+		ModuleName: "test",
+		Instances:  2,
+		OutOfTree:  false,
+		Unsigned:   false,
+	}
+	e := `{"moduleName":"test","instances":2,"proprietary":false,"outOfTree":false,"unsigned":false}`
+	assert.Equal(t,
+		e, fmt.Sprintf("%v", v), "ModuleStat string is invalid: %v", v)
+
+}