Address comments in PR 1861

Refactor configuring logging into a reusable component
so that it can be nicely used in both main() and init process init()

Co-authored-by: Georgi Sabev <georgethebeatle@gmail.com>
Co-authored-by: Giuseppe Capizzi <gcapizzi@pivotal.io>
Co-authored-by: Claudia Beresford <cberesford@pivotal.io>
Signed-off-by: Danail Branekov <danailster@gmail.com>

libcontainer/process_linux.go

@@ -13,6 +13,8 @@ import (
 	"strconv"
 	"syscall" // only for Signal
 
+	"github.com/opencontainers/runc/libcontainer/logs"
+
 	"github.com/opencontainers/runc/libcontainer/cgroups"
 	"github.com/opencontainers/runc/libcontainer/configs"
 	"github.com/opencontainers/runc/libcontainer/intelrdt"
@@ -48,10 +50,10 @@ type parentProcess interface {
 
 	setExternalDescriptors(fds []string)
 
-	getChildLogs()
+	forwardChildLogs()
 }
 
-type pipePair struct {
+type readWritePair struct {
 	r *os.File
 	w *os.File
 }
@@ -60,7 +62,7 @@ type setnsProcess struct {
 	cmd             *exec.Cmd
 	parentPipe      *os.File
 	childPipe       *os.File
-	logPipe         pipePair
+	logPipe         readWritePair
 	cgroupPaths     map[string]string
 	rootlessCgroups bool
 	intelRdtPath    string
@@ -215,15 +217,15 @@ func (p *setnsProcess) setExternalDescriptors(newFds []string) {
 	p.fds = newFds
 }
 
-func (p *setnsProcess) getChildLogs() {
-	go forwardLogs(p.logPipe.r)
+func (p *setnsProcess) forwardChildLogs() {
+	go logs.ForwardLogs(p.logPipe.r)
 }
 
 type initProcess struct {
 	cmd             *exec.Cmd
 	parentPipe      *os.File
 	childPipe       *os.File
-	logPipe         pipePair
+	logPipe         readWritePair
 	config          *initConfig
 	manager         cgroups.Manager
 	intelRdtManager intelrdt.Manager
@@ -525,8 +527,8 @@ func (p *initProcess) setExternalDescriptors(newFds []string) {
 	p.fds = newFds
 }
 
-func (p *initProcess) getChildLogs() {
-	go forwardLogs(p.logPipe.r)
+func (p *initProcess) forwardChildLogs() {
+	go logs.ForwardLogs(p.logPipe.r)
 }
 
 func getPipeFds(pid int) ([]string, error) {