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processmon.go
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processmon.go
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// Package processmon is to manage and monitor remote enforcers.
package processmon
import (
"bufio"
"errors"
"fmt"
"io"
"os"
"os/exec"
"path/filepath"
"strconv"
"syscall"
"time"
"go.uber.org/zap"
"github.com/aporeto-inc/trireme-lib/controller/constants"
"github.com/aporeto-inc/trireme-lib/controller/internal/enforcer/utils/rpcwrapper"
"github.com/aporeto-inc/trireme-lib/controller/pkg/remoteenforcer"
"github.com/aporeto-inc/trireme-lib/utils/cache"
"github.com/aporeto-inc/trireme-lib/utils/crypto"
"github.com/kardianos/osext"
)
var (
// launcher supports only a global processMon instance
launcher *processMon
)
const (
// netNSPath holds the directory to ensure ip netns command works
netNSPath = "/var/run/netns/"
processMonitorCacheName = "ProcessMonitorCache"
secretLength = 32
)
// processMon is an instance of processMonitor
type processMon struct {
// netNSPath made configurable to enable running tests
netNSPath string
activeProcesses *cache.Cache
childExitStatus chan exitStatus
// logToConsole stores if we should log to console.
logToConsole bool
// logWithID is the ID for for log files if logging to file.
logWithID bool
// logLevel is the level of logs for remote command.
logLevel string
logFormat string
}
// processInfo stores per process information
type processInfo struct {
contextID string
RPCHdl rpcwrapper.RPCClient
process *os.Process
}
// exitStatus captures the exit status of a process
type exitStatus struct {
process int
// The contextID is optional and is primarily used by remote enforcer
// processes to represent the namespace in which the process was running
contextID string
exitStatus error
}
func init() {
// Setup new launcher
newProcessMon(netNSPath)
}
// contextID2SocketPath returns the socket path to use for a givent context
func contextID2SocketPath(contextID string) string {
if contextID == "" {
panic("contextID is empty")
}
return filepath.Join("/var/run/", contextID+".sock")
}
// processIOReader will read from a reader and print it on the calling process
func processIOReader(fd io.Reader, contextID string, exited chan int) {
reader := bufio.NewReader(fd)
for {
str, err := reader.ReadString('\n')
if err != nil {
exited <- 1
return
}
fmt.Print("[" + contextID + "]:" + str)
}
}
// newProcessMon is a method to create a new processmon
func newProcessMon(netns string) ProcessManager {
launcher = &processMon{
netNSPath: netns,
activeProcesses: cache.NewCache(processMonitorCacheName),
childExitStatus: make(chan exitStatus, 100),
}
go launcher.collectChildExitStatus()
return launcher
}
// GetProcessManagerHdl returns a process manager handle.
func GetProcessManagerHdl() ProcessManager {
return launcher
}
// collectChildExitStatus is an async function which collects status for all launched child processes
func (p *processMon) collectChildExitStatus() {
for {
es := <-p.childExitStatus
zap.L().Debug("Remote enforcer exited",
zap.String("nativeContextID", es.contextID),
zap.Int("pid", es.process),
zap.Error(es.exitStatus),
)
}
}
// SetLogParameters setups args that should be propagated to child processes
func (p *processMon) SetLogParameters(logToConsole, logWithID bool, logLevel string, logFormat string) {
p.logToConsole = logToConsole
p.logWithID = logWithID
p.logLevel = logLevel
p.logFormat = logFormat
}
// KillProcess sends a rpc to the process to exit failing which it will kill the process
func (p *processMon) KillProcess(contextID string) {
s, err := p.activeProcesses.Get(contextID)
if err != nil {
zap.L().Debug("Process already killed or never launched")
return
}
procInfo, ok := s.(*processInfo)
if !ok {
return
}
req := &rpcwrapper.Request{}
resp := &rpcwrapper.Response{}
req.Payload = procInfo.process.Pid
c := make(chan error, 1)
go func() {
c <- procInfo.RPCHdl.RemoteCall(contextID, remoteenforcer.EnforcerExit, req, resp)
}()
select {
case err := <-c:
if err != nil {
zap.L().Debug("Failed to stop gracefully",
zap.String("Remote error", err.Error()))
}
if err := procInfo.process.Kill(); err != nil {
zap.L().Debug("Process is already dead",
zap.String("Kill error", err.Error()))
}
case <-time.After(5 * time.Second):
if err := procInfo.process.Kill(); err != nil {
zap.L().Info("Time out while killing process ",
zap.Error(err))
}
}
procInfo.RPCHdl.DestroyRPCClient(contextID)
if err := os.Remove(filepath.Join(p.netNSPath, contextID)); err != nil {
zap.L().Warn("Failed to remote process from netns path", zap.Error(err))
}
if err := p.activeProcesses.Remove(contextID); err != nil {
zap.L().Warn("Failed to remote process from cache", zap.Error(err))
}
}
// pollStdOutAndErr polls std out and err
func (p *processMon) pollStdOutAndErr(
cmd *exec.Cmd,
exited chan int,
contextID string,
) (initializedCount int, err error) {
stdout, err := cmd.StdoutPipe()
if err != nil {
return initializedCount, err
}
initializedCount++
stderr, err := cmd.StderrPipe()
if err != nil {
return initializedCount, err
}
initializedCount++
// Stdout/err processing
go processIOReader(stdout, contextID, exited)
go processIOReader(stderr, contextID, exited)
return initializedCount, nil
}
// getLaunchProcessCmd returns the command used to launch the enforcerd
func (p *processMon) getLaunchProcessCmd(arg string) (*exec.Cmd, error) {
cmdName, err := osext.Executable()
if err != nil {
return nil, err
}
cmdArgs := []string{arg}
zap.L().Debug("Enforcer executed",
zap.String("command", cmdName),
zap.Strings("args", cmdArgs),
)
return exec.Command(cmdName, cmdArgs...), nil
}
// getLaunchProcessEnvVars returns a slice of env variable strings where each string is in the form of key=value
func (p *processMon) getLaunchProcessEnvVars(
procMountPoint string,
contextID string,
randomkeystring string,
statsServerSecret string,
refPid int,
refNSPath string,
) []string {
newEnvVars := []string{
constants.EnvMountPoint + "=" + procMountPoint,
constants.EnvContextSocket + "=" + contextID2SocketPath(contextID),
constants.EnvStatsChannel + "=" + rpcwrapper.StatsChannel,
constants.EnvRPCClientSecret + "=" + randomkeystring,
constants.EnvStatsSecret + "=" + statsServerSecret,
constants.EnvContainerPID + "=" + strconv.Itoa(refPid),
constants.EnvLogLevel + "=" + p.logLevel,
constants.EnvLogFormat + "=" + p.logFormat,
}
if p.logToConsole {
newEnvVars = append(newEnvVars, constants.EnvLogToConsole+"="+constants.EnvLogToConsoleEnable)
} else if p.logWithID {
newEnvVars = append(newEnvVars, constants.EnvLogID+"="+contextID)
}
// If the PURuntime Specified a NSPath, then it is added as a new env var also.
if refNSPath != "" {
newEnvVars = append(newEnvVars, constants.EnvNSPath+"="+refNSPath)
}
return newEnvVars
}
// LaunchProcess prepares the environment and launches the process
func (p *processMon) LaunchProcess(
contextID string,
refPid int,
refNSPath string,
rpchdl rpcwrapper.RPCClient,
arg string,
statsServerSecret string,
procMountPoint string,
) error {
if _, err := p.activeProcesses.Get(contextID); err == nil {
return nil
}
// We check if the NetNsPath was given as parameter.
// If it was we will use it. Otherwise we will determine it based on the PID.
nsPath := refNSPath
if refNSPath == "" {
nsPath = filepath.Join(procMountPoint, strconv.Itoa(refPid), "ns/net")
}
hoststat, err := os.Stat(filepath.Join(procMountPoint, "1/ns/net"))
if err != nil {
return err
}
pidstat, err := os.Stat(nsPath)
if err != nil {
return fmt.Errorf("container pid %d not found: %s", refPid, err)
}
if pidstat.Sys().(*syscall.Stat_t).Ino == hoststat.Sys().(*syscall.Stat_t).Ino {
return errors.New("refused to launch a remote enforcer in host namespace")
}
if _, err = os.Stat(p.netNSPath); err != nil {
err = os.MkdirAll(p.netNSPath, os.ModeDir)
if err != nil {
zap.L().Warn("could not create directory", zap.Error(err))
}
}
// A symlink is created from /var/run/netns/<context> to the NetNSPath
contextFile := filepath.Join(p.netNSPath, contextID)
if _, err = os.Stat(contextFile); err != nil {
if err = os.Symlink(nsPath, contextFile); err != nil {
zap.L().Warn("Failed to create symlink for use by ip netns", zap.Error(err))
}
}
cmd, err := p.getLaunchProcessCmd(arg)
if err != nil {
return fmt.Errorf("enforcer binary not found: %s", err)
}
exited := make(chan int, 2)
waitForExitCount := 0
if p.logToConsole {
if waitForExitCount, err = p.pollStdOutAndErr(cmd, exited, contextID); err != nil {
return err
}
}
randomkeystring, err := crypto.GenerateRandomString(secretLength)
if err != nil {
// This is a more serious failure. We can't reliably control the remote enforcer
return fmt.Errorf("unable to generate secret: %s", err)
}
// Start command
newEnvVars := p.getLaunchProcessEnvVars(
procMountPoint,
contextID,
randomkeystring,
statsServerSecret,
refPid,
refNSPath,
)
cmd.Env = append(os.Environ(), newEnvVars...)
if err = cmd.Start(); err != nil {
// Cleanup resources
if err1 := os.Remove(contextFile); err1 != nil {
zap.L().Warn("Failed to clean up netns path", zap.Error(err1))
}
return fmt.Errorf("unable to start enforcer binary: %s", err)
}
go func() {
for i := 0; i < waitForExitCount; i++ {
<-exited
}
status := cmd.Wait()
p.childExitStatus <- exitStatus{
process: cmd.Process.Pid,
contextID: contextID,
exitStatus: status,
}
}()
if err := rpchdl.NewRPCClient(contextID, contextID2SocketPath(contextID), randomkeystring); err != nil {
return err
}
p.activeProcesses.AddOrUpdate(contextID, &processInfo{
contextID: contextID,
process: cmd.Process,
RPCHdl: rpchdl})
return nil
}