use warewulf.conf from parent on child

The directories for the overlays needed for the bind
mount are now created under conf.Paths.WWChrootdir/$CONTAINERNAME
with the pattern $CONTAINERNAME-run-xxxxxx. This pattern can be
used as lock, so that there can't be congruent shell/exec calls
to the same container.

Signed-off-by: Christian Goll <cgoll@suse.com>

internal/app/wwctl/container/exec/child/main.go

@@ -21,7 +21,7 @@ import (
 	"github.com/warewulf/warewulf/internal/pkg/wwlog"
 )
 
-const exitEval = `$(VALU="$?" ; if [ $VALU == 0 ]; then echo write; else echo discard; fi)`
+const exitEval = `$(VALU="$?" ; if [ $VALU == 0 ]; then echo create new image; else echo no new image; fi)`
 
 func CobraRunE(cmd *cobra.Command, args []string) (err error) {
 	if os.Getpid() != 1 {

internal/app/wwctl/container/exec/main.go

@@ -4,15 +4,18 @@
 package exec
 
 import (
+	"errors"
 	"fmt"
 	"os"
 	"os/exec"
 	"path"
+	"path/filepath"
 	"syscall"
 	"time"
 
-	"github.com/spf13/cobra"
 	warewulfconf "github.com/warewulf/warewulf/internal/pkg/config"
+
+	"github.com/spf13/cobra"
 	"github.com/warewulf/warewulf/internal/pkg/container"
 	"github.com/warewulf/warewulf/internal/pkg/util"
 	"github.com/warewulf/warewulf/internal/pkg/wwlog"
@@ -22,22 +25,21 @@ import (
 fork off a process with a new PID space
 */
 func runContainedCmd(args []string) (err error) {
-	if overlayDir == "" {
-		conf := warewulfconf.Get()
-		overlayDir, err = os.MkdirTemp(conf.Paths.WWChrootdir, "overlays-")
-		if err != nil {
-			wwlog.Warn("couldn't create temp dir for overlay", err)
-		}
-		defer func() {
-			err = os.RemoveAll(overlayDir)
-			if err != nil {
-				wwlog.Warn("Couldn't remove temp dir for ephermal mounts:", err)
-			}
-		}()
+	conf := warewulfconf.Get()
+	if matches, _ := filepath.Glob(path.Join(conf.Paths.WWChrootdir, args[0], args[0]) + "-run-*"); len(matches) > 0 {
+		return fmt.Errorf("found lock directories for container: %v", matches)
 	}
+	overlayDir, err = os.MkdirTemp(path.Join(conf.Paths.WWChrootdir, args[0]), args[0]+"-run-")
+	if err != nil {
+		wwlog.Warn("couldn't create temp dir for overlay", err)
+	}
+	defer func() {
+		err = errors.Join(os.RemoveAll(overlayDir), err)
+	}()
+
 	logStr := fmt.Sprint(wwlog.GetLogLevel())
 	wwlog.Verbose("Running contained command: %s", args[1:])
-	c := exec.Command("/proc/self/exe", append([]string{"--loglevel", logStr, "--overlaydir", overlayDir, "container", "exec", "__child"}, args...)...)
+	c := exec.Command("/proc/self/exe", append([]string{"--warewulfconf", conf.GetWarewulfConf(), "--loglevel", logStr, "--overlaydir", overlayDir, "container", "exec", "__child"}, args...)...)
 
 	c.SysProcAttr = &syscall.SysProcAttr{
 		Cloneflags: syscall.CLONE_NEWUTS | syscall.CLONE_NEWPID | syscall.CLONE_NEWNS,

internal/pkg/config/root.go

@@ -42,14 +42,14 @@ type RootConf struct {
 	MountsContainer []*MountEntry `yaml:"container mounts" default:"[{\"source\": \"/etc/resolv.conf\", \"dest\": \"/etc/resolv.conf\"}]"`
 	Paths           *BuildConfig  `yaml:"paths"`
 
-	fromFile bool
+	warewulfconf string
 }
 
 // New caches and returns a new [RootConf] initialized with empty
 // values, clearing replacing any previously cached value.
 func New() *RootConf {
 	cachedConf = RootConf{}
-	cachedConf.fromFile = false
+	cachedConf.warewulfconf = ""
 	cachedConf.Warewulf = new(WarewulfConf)
 	cachedConf.DHCP = new(DHCPConf)
 	cachedConf.TFTP = new(TFTPConf)
@@ -77,12 +77,12 @@ func Get() *RootConf {
 // file.
 func (conf *RootConf) Read(confFileName string) error {
 	wwlog.Debug("Reading warewulf.conf from: %s", confFileName)
+	conf.warewulfconf = confFileName
 	if data, err := os.ReadFile(confFileName); err != nil {
 		return err
 	} else if err := conf.Parse(data); err != nil {
 		return err
 	} else {
-		conf.fromFile = true
 		return nil
 	}
 }
@@ -200,5 +200,9 @@ func (conf *RootConf) SetDynamicDefaults() (err error) {
 // InitializedFromFile returns true if [RootConf] memory was read from
 // a file, or false otherwise.
 func (conf *RootConf) InitializedFromFile() bool {
-	return conf.fromFile
+	return conf.warewulfconf != ""
+}
+
+func (conf *RootConf) GetWarewulfConf() string {
+	return conf.warewulfconf
 }

internal/pkg/config/root_test.go

@@ -67,6 +67,7 @@ func TestInitializedFromFile(t *testing.T) {
 	assert.False(t, conf.InitializedFromFile())
 	assert.NoError(t, conf.Read(tempWarewulfConf.Name()))
 	assert.True(t, conf.InitializedFromFile())
+	assert.Equal(t, conf.GetWarewulfConf(), tempWarewulfConf.Name())
 }
 
 func TestExampleRootConf(t *testing.T) {