added support for mounts.conf for container exec

Makefile

@@ -97,7 +97,7 @@ export GOPROXY
 WW_GO_BUILD_TAGS := containers_image_openpgp containers_image_ostree
 
 # Default target
-all: config vendor wwctl wwclient bash_completion.d man_pages config_defaults print_defaults wwapid wwapic wwapird
+all: config vendor wwctl wwclient bash_completion.d man_pages config_defaults print_defaults wwapid wwapic wwapird print_mnts
 
 # Validate source and build all packages
 build: lint test-it vet all
@@ -248,6 +248,9 @@ config_defaults: vendor cmd/config_defaults/config_defaults.go
 print_defaults: vendor cmd/print_defaults/print_defaults.go
 	cd cmd/print_defaults && go build -ldflags="-X 'github.com/hpcng/warewulf/internal/pkg/warewulfconf.ConfigFile=./etc/warewulf.conf'" -o ../../print_defaults
 
+print_mnts: vendor cmd/print_mnts/print_mnts.go
+	cd cmd/print_mnts && go build -ldflags="-X 'github.com/hpcng/warewulf/internal/pkg/warewulfconf.ConfigFile=./etc/warewulf.conf'" -o ../../print_mnts
+
 update_configuration: vendor cmd/update_configuration/update_configuration.go
 	cd cmd/update_configuration && go build -ldflags="-X 'github.com/hpcng/warewulf/internal/pkg/warewulfconf.ConfigFile=./etc/warewulf.conf'\
 	 -X 'github.com/hpcng/warewulf/internal/pkg/node.ConfigFile=./etc/nodes.conf'"\
@@ -309,6 +312,7 @@ clean:
 	rm -f config_defaults
 	rm -f update_configuration
 	rm -f print_defaults
+	rm -f print_mnts
 	rm -f etc/wwapi{c,d,rd}.conf
 
 install: files install_wwclient

cmd/print_mnts/print_mnts.go

@@ -0,0 +1,37 @@
+package print_mnts
+
+import (
+	"fmt"
+
+	"github.com/hpcng/warewulf/internal/pkg/container"
+	"gopkg.in/yaml.v2"
+)
+
+func main() {
+	mounts := []container.MntDetails{
+		container.MntDetails{
+			Source:   "/etc/resolv.conf",
+			Dest:     "/etc/resolv.conf",
+			ReadOnly: false,
+		},
+		container.MntDetails{
+			Source:   "etc/zypp/credentials.d/SCCcredentials",
+			Dest:     "etc/zypp/credentials.d/SCCcredentials",
+			ReadOnly: false,
+		},
+		container.MntDetails{
+			Source:   "/etc/SUSEConnect",
+			Dest:     "/etc/SUSEConnect",
+			ReadOnly: false,
+		},
+	}
+	var ptrs []*container.MntDetails
+	for _, m := range mounts {
+		ptrs = append(ptrs, &m)
+	}
+	mountPts := container.MountPoints{
+		MountPnts: ptrs,
+	}
+	data, _ := yaml.Marshal(mountPts)
+	fmt.Println(data)
+}

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

@@ -32,8 +32,10 @@ func CobraRunE(cmd *cobra.Command, args []string) error {
 		os.Exit(1)
 	}
 	var err error
+	mountPts := container.DefaultMntPts()
+	mountPts = append(container.InitMountPnts(binds), mountPts...)
 	// check for valid mount points
-	lowerObjects := checkMountPoints(containerName, binds)
+	lowerObjects := checkMountPoints(containerName, mountPts)
 	if len(lowerObjects) != 0 {
 		if tempDir == "" {
 			tempDir, err = os.MkdirTemp(buildconfig.TMPDIR(), "overlay")
@@ -154,33 +156,22 @@ func CobraRunE(cmd *cobra.Command, args []string) error {
 Check if the bind mount points exists in the given container. Returns
 the invalid mount points. Directories always have '/' as suffix
 */
-func checkMountPoints(containerName string, binds []string) (overlayObjects []string) {
+func checkMountPoints(containerName string, binds []container.MntDetails) (overlayObjects []string) {
 	wwlog.Debug("Checking if container %s has paths: %v", containerName, binds)
 	overlayObjects = []string{}
 	for _, b := range binds {
-		var source string
-		var dest string
-
-		bind := util.SplitValidPaths(b, ":")
-		source = bind[0]
-
-		if len(bind) == 1 {
-			dest = source
-		} else {
-			dest = bind[1]
-		}
-		err, _ := os.Stat(source)
+		err, _ := os.Stat(b.Source)
 		if err == nil {
 			// no need to create a mount location if source doesn't exist
 			continue
 		}
-		if _, err := os.Stat(path.Join(container.RootFsDir(containerName), dest)); err != nil {
+		if _, err := os.Stat(path.Join(container.RootFsDir(containerName), b.Dest)); err != nil {
 			if os.IsNotExist(err) {
-				if util.IsDir(dest) && !strings.HasSuffix(dest, "/") {
-					dest += "/"
+				if util.IsDir(b.Dest) && !strings.HasSuffix(b.Dest, "/") {
+					b.Dest += "/"
 				}
-				overlayObjects = append(overlayObjects, source)
-				wwlog.Debug("Container %s, needs following path: %s", containerName, dest)
+				overlayObjects = append(overlayObjects, b.Dest)
+				wwlog.Debug("Container %s, needs following path: %s", containerName, b.Dest)
 			}
 		}
 	}

internal/pkg/container/mountpoints.go

@@ -0,0 +1,73 @@
+package container
+
+import (
+	"io/ioutil"
+	"path"
+	"strings"
+
+	"github.com/hpcng/warewulf/internal/pkg/buildconfig"
+	"github.com/hpcng/warewulf/internal/pkg/wwlog"
+	"gopkg.in/yaml.v2"
+)
+
+/*
+Describe a mount point for a container exec
+*/
+type MntDetails struct {
+	Dest     string `yaml:"Dest"`
+	Source   string `yaml:"Source,omitempty"`
+	ReadOnly bool   `yaml:"Readonly,omitempty" default:"false"`
+	Options  string `yaml:"Options,omitempty"` // ignored at the moment
+}
+
+/*
+Holds the containers, so that they can be marshalled
+*/
+type MountPoints struct {
+	MountPnts []*MntDetails `yaml:"Mount Points"`
+}
+
+/*
+Create a slice iof MntDetails from a string slice with following
+format "source:[:destination][:readonly]" if destination is not
+given, the source is used as destination
+*/
+func InitMountPnts(binds []string) (mounts []MntDetails) {
+	for _, b := range binds {
+		bind := strings.Split(b, ":")
+		dest := bind[0]
+		if len(bind) >= 2 {
+			dest = bind[1]
+		}
+		readonly := false
+		if len(bind) >= 3 && bind[2] == "ro" {
+			readonly = true
+		}
+		mntPnt := MntDetails{
+			Source:   bind[0],
+			Dest:     dest,
+			ReadOnly: readonly,
+		}
+		mounts = append(mounts, mntPnt)
+	}
+	return mounts
+}
+
+/*
+Read in the default bind mounts from the configuration file
+
+	warewulf/mounts.conf
+*/
+func DefaultMntPts() (mounts []MntDetails) {
+	data, err := ioutil.ReadFile(path.Join(buildconfig.SYSCONFDIR(), "warewulf/mounts.conf"))
+	if err != nil {
+		wwlog.Verbose("No default bind mounts for containers: %s", err)
+		return mounts
+	}
+	wwlog.Debug("Unmarshaling the mounts configuration")
+	err = yaml.Unmarshal(data, &mounts)
+	if err != nil {
+		wwlog.Verbose("Couldn't unmarshall default bind mounts for containers: %s", err)
+	}
+	return mounts
+}