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agent: parse kernel command line as soon as possible
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The kernel command line should be parsed as soon as possible to allow the agent
setup the system according to the configuration, for example what `initMounts`
it has to mount or not.

Signed-off-by: Julio Montes <[email protected]>
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Julio Montes committed Mar 4, 2020
1 parent 56190a9 commit ddd9188
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Showing 3 changed files with 50 additions and 98 deletions.
15 changes: 9 additions & 6 deletions agent.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -177,6 +177,9 @@ var debugConsoleVSockPort = uint32(0)
// Timeout waiting for a device to be hotplugged
var hotplugTimeout = 3 * time.Second

// Specify the log level
var logLevel = defaultLogLevel

// commType is used to denote the communication channel type used.
type commType int

Expand Down Expand Up @@ -984,12 +987,7 @@ func logsToVPort() {
func (s *sandbox) initLogger(ctx context.Context) error {
agentLog.Logger.Formatter = &logrus.TextFormatter{DisableColors: true, TimestampFormat: time.RFC3339Nano}

config := newConfig(defaultLogLevel)
if err := config.getConfig(kernelCmdlineFile); err != nil {
agentLog.WithError(err).Warn("Failed to get config from kernel cmdline")
}

agentLog.Logger.SetLevel(config.logLevel)
agentLog.Logger.SetLevel(logLevel)

agentLog = agentLog.WithField("debug_console", debugConsole)

Expand Down Expand Up @@ -1426,6 +1424,9 @@ func initAgentAsInit() error {
if err := generalMount(); err != nil {
return err
}
if err := parseKernelCmdline(); err != nil {
return err
}
if err := cgroupsMount(); err != nil {
return err
}
Expand Down Expand Up @@ -1477,6 +1478,8 @@ func realMain() error {
if err = initAgentAsInit(); err != nil {
panic(fmt.Sprintf("failed to setup agent as init: %v", err))
}
} else if err := parseKernelCmdline(); err != nil {
return err
}

r := &agentReaper{}
Expand Down
24 changes: 7 additions & 17 deletions config.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -27,38 +27,28 @@ const (
debugConsoleFlag = optionPrefix + "debug_console"
debugConsoleVPortFlag = optionPrefix + "debug_console_vport"
hotplugTimeoutFlag = optionPrefix + "hotplug_timeout"
kernelCmdlineFile = "/proc/cmdline"
traceModeStatic = "static"
traceModeDynamic = "dynamic"
traceTypeIsolated = "isolated"
traceTypeCollated = "collated"
defaultTraceType = traceTypeIsolated
)

type agentConfig struct {
logLevel logrus.Level
}

func newConfig(level logrus.Level) agentConfig {
return agentConfig{
logLevel: level,
}
}
var kernelCmdlineFile = "/proc/cmdline"

//Get the agent configuration from kernel cmdline
func (c *agentConfig) getConfig(cmdLineFile string) error {
if cmdLineFile == "" {
func parseKernelCmdline() error {
if kernelCmdlineFile == "" {
return grpcStatus.Error(codes.FailedPrecondition, "Kernel cmdline file cannot be empty")
}

kernelCmdline, err := ioutil.ReadFile(cmdLineFile)
kernelCmdline, err := ioutil.ReadFile(kernelCmdlineFile)
if err != nil {
return err
}

words := strings.Fields(string(kernelCmdline))
for _, word := range words {
if err := c.parseCmdlineOption(word); err != nil {
if err := parseCmdlineOption(word); err != nil {
agentLog.WithFields(logrus.Fields{
"error": err,
"option": word,
Expand All @@ -70,7 +60,7 @@ func (c *agentConfig) getConfig(cmdLineFile string) error {
}

//Parse a string that represents a kernel cmdline option
func (c *agentConfig) parseCmdlineOption(option string) error {
func parseCmdlineOption(option string) error {
const (
optionPosition = iota
valuePosition
Expand Down Expand Up @@ -106,7 +96,7 @@ func (c *agentConfig) parseCmdlineOption(option string) error {
if err != nil {
return err
}
c.logLevel = level
logLevel = level
if level == logrus.DebugLevel {
debug = true
}
Expand Down
109 changes: 34 additions & 75 deletions config_test.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -9,73 +9,47 @@ package main
import (
"io/ioutil"
"os"
"reflect"
"testing"
"time"

"github.com/sirupsen/logrus"
"github.com/stretchr/testify/assert"
)

func TestNewConfig(t *testing.T) {
assert := assert.New(t)

testLogLevel := logrus.DebugLevel

expectedConfig := agentConfig{
logLevel: testLogLevel,
}

config := newConfig(testLogLevel)

assert.True(reflect.DeepEqual(config, expectedConfig),
"Config structures should be identical: got %+v, expecting %+v",
config, expectedConfig)
}

func TestParseCmdlineOptionEmptyOption(t *testing.T) {
assert := assert.New(t)

a := &agentConfig{}

err := a.parseCmdlineOption("")
err := parseCmdlineOption("")
assert.NoError(err, "%v", err)
}

func TestParseCmdlineOptionWrongOptionValue(t *testing.T) {
assert := assert.New(t)

a := &agentConfig{}

wrongOption := logLevelFlag + "=debgu"

err := a.parseCmdlineOption(wrongOption)
err := parseCmdlineOption(wrongOption)
assert.Errorf(err, "Parsing should fail because wrong option %q", wrongOption)
}

func TestParseCmdlineOptionWrongOptionParam(t *testing.T) {
assert := assert.New(t)

a := &agentConfig{}

wrongOption := "agent.lgo=debug"

err := a.parseCmdlineOption(wrongOption)
err := parseCmdlineOption(wrongOption)
assert.Errorf(err, "Parsing should fail because wrong option %q", wrongOption)
}

func TestParseCmdlineOptionCorrectOptions(t *testing.T) {
assert := assert.New(t)

a := &agentConfig{}

logFlagList := []string{"debug", "info", "warn", "error", "fatal", "panic"}

for _, logFlag := range logFlagList {
debug = false
option := logLevelFlag + "=" + logFlag

err := a.parseCmdlineOption(option)
err := parseCmdlineOption(option)
assert.NoError(err, "%v", err)

if logFlag == "debug" {
Expand All @@ -87,23 +61,19 @@ func TestParseCmdlineOptionCorrectOptions(t *testing.T) {
func TestParseCmdlineOptionIncorrectOptions(t *testing.T) {
assert := assert.New(t)

a := &agentConfig{}

logFlagList := []string{"debg", "ifo", "wan", "eror", "ftal", "pnic"}

for _, logFlag := range logFlagList {
option := logLevelFlag + "=" + logFlag

err := a.parseCmdlineOption(option)
err := parseCmdlineOption(option)
assert.Errorf(err, "Should fail because of incorrect option %q", logFlag)
}
}

func TestParseCmdlineOptionDevMode(t *testing.T) {
assert := assert.New(t)

a := &agentConfig{}

type testData struct {
option string
expectDevModeEnabled bool
Expand All @@ -126,7 +96,7 @@ func TestParseCmdlineOptionDevMode(t *testing.T) {
debug = false
crashOnError = false

err := a.parseCmdlineOption(d.option)
err := parseCmdlineOption(d.option)
assert.NoError(err)

if !d.expectDevModeEnabled {
Expand All @@ -138,20 +108,9 @@ func TestParseCmdlineOptionDevMode(t *testing.T) {
}
}

func TestGetConfigEmptyFileName(t *testing.T) {
assert := assert.New(t)

a := &agentConfig{}

err := a.getConfig("")
assert.Error(err, "Should fail because command line path is empty")
}

func TestGetConfigFilePathNotExist(t *testing.T) {
assert := assert.New(t)

a := &agentConfig{}

tmpFile, err := ioutil.TempFile("", "test")
assert.NoError(err, "%v", err)

Expand All @@ -160,15 +119,17 @@ func TestGetConfigFilePathNotExist(t *testing.T) {
err = os.Remove(fileName)
assert.NoError(err, "%v", err)

err = a.getConfig(fileName)
assert.Error(err, "Should fail because command line path does not exist")
kernelCmdlineFileOld := kernelCmdlineFile
defer func() {
kernelCmdlineFile = kernelCmdlineFileOld
}()
kernelCmdlineFile = fileName
assert.Error(parseKernelCmdline())
}

func TestGetConfig(t *testing.T) {
func TestParseKernelCmdline(t *testing.T) {
assert := assert.New(t)

a := &agentConfig{}

tmpFile, err := ioutil.TempFile("", "test")
assert.NoError(err, "%v", err)
fileName := tmpFile.Name()
Expand All @@ -178,12 +139,17 @@ func TestGetConfig(t *testing.T) {

defer os.Remove(fileName)

err = a.getConfig(fileName)
assert.NoError(err, "%v", err)
kernelCmdlineFileOld := kernelCmdlineFile
defer func() {
kernelCmdlineFile = kernelCmdlineFileOld
}()
kernelCmdlineFile = fileName

assert.NoError(parseKernelCmdline())

assert.True(a.logLevel == logrus.InfoLevel,
assert.True(logLevel == logrus.InfoLevel,
"Log levels should be identical: got %+v, expecting %+v",
a.logLevel, logrus.InfoLevel)
logLevel, logrus.InfoLevel)
}

func TestParseCmdlineOptionTracing(t *testing.T) {
Expand Down Expand Up @@ -214,14 +180,17 @@ func TestParseCmdlineOptionTracing(t *testing.T) {
{traceModeFlag + "=" + traceTypeCollated + "x", false, false},
}

kernelCmdlineFileOld := kernelCmdlineFile
defer func() {
kernelCmdlineFile = kernelCmdlineFileOld
}()

for i, d := range data {
// force reset
tracing = false
collatedTrace = false
debug = false

a := &agentConfig{}

tmpFile, err := ioutil.TempFile("", "")
assert.NoError(err)

Expand All @@ -235,8 +204,8 @@ func TestParseCmdlineOptionTracing(t *testing.T) {
assert.False(collatedTrace)
assert.False(debug)

err = a.getConfig(fileName)
assert.NoError(err)
kernelCmdlineFile = fileName
assert.NoError(parseKernelCmdline())

if d.expectTraceEnabled {
assert.Truef(tracing, "test %d (%+v)", i, d)
Expand Down Expand Up @@ -296,19 +265,15 @@ func TestParseCmdlineOptionWrongOptionVsock(t *testing.T) {
t.Skip()
assert := assert.New(t)

a := &agentConfig{}

wrongOption := "use_vsockkk=true"

err := a.parseCmdlineOption(wrongOption)
err := parseCmdlineOption(wrongOption)
assert.Errorf(err, "Parsing should fail because wrong option %q", wrongOption)
}

func TestParseCmdlineOptionsVsock(t *testing.T) {
assert := assert.New(t)

a := &agentConfig{}

type testData struct {
val string
shouldErr bool
Expand All @@ -325,7 +290,7 @@ func TestParseCmdlineOptionsVsock(t *testing.T) {
commCh = unknownCh
option := useVsockFlag + "=" + d.val

err := a.parseCmdlineOption(option)
err := parseCmdlineOption(option)
if d.shouldErr {
assert.Error(err)
} else {
Expand All @@ -338,8 +303,6 @@ func TestParseCmdlineOptionsVsock(t *testing.T) {
func TestParseCmdlineOptionDebugConsole(t *testing.T) {
assert := assert.New(t)

a := &agentConfig{}

type testData struct {
option string
expectDebugConsoleEnabled bool
Expand All @@ -357,7 +320,7 @@ func TestParseCmdlineOptionDebugConsole(t *testing.T) {
for i, d := range data {
debugConsole = false

err := a.parseCmdlineOption(d.option)
err := parseCmdlineOption(d.option)
assert.NoError(err)

if !d.expectDebugConsoleEnabled {
Expand All @@ -371,8 +334,6 @@ func TestParseCmdlineOptionDebugConsole(t *testing.T) {
func TestParseCmdlineOptionDebugConsoleVPort(t *testing.T) {
assert := assert.New(t)

a := &agentConfig{}

type testData struct {
option string
expectDebugConsoleEnabled bool
Expand All @@ -395,7 +356,7 @@ func TestParseCmdlineOptionDebugConsoleVPort(t *testing.T) {
debugConsole = false
debugConsoleVSockPort = 0

err := a.parseCmdlineOption(d.option)
err := parseCmdlineOption(d.option)
if d.expectedError {
assert.Error(err)
} else {
Expand All @@ -413,8 +374,6 @@ func TestParseCmdlineOptionDebugConsoleVPort(t *testing.T) {
func TestParseCmdlineOptionHotplugTimeout(t *testing.T) {
assert := assert.New(t)

a := &agentConfig{}

type testData struct {
option string
shouldErr bool
Expand All @@ -441,7 +400,7 @@ func TestParseCmdlineOptionHotplugTimeout(t *testing.T) {
// reset the hotplug timeout
hotplugTimeout = 3 * time.Second

err := a.parseCmdlineOption(d.option)
err := parseCmdlineOption(d.option)
if d.shouldErr {
assert.Error(err)
} else {
Expand Down

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