Added wwctl container exec ... feature

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

@@ -0,0 +1,48 @@
+// + build linux
+
+package child
+
+import (
+	"fmt"
+	"github.com/hpcng/warewulf/internal/pkg/container"
+	"github.com/hpcng/warewulf/internal/pkg/wwlog"
+	"github.com/spf13/cobra"
+	"os"
+	"syscall"
+)
+
+func CobraRunE(cmd *cobra.Command, args []string) error {
+
+	if os.Getpid() != 1 {
+		wwlog.Printf(wwlog.ERROR, "PID is not 1: %d\n", os.Getpid())
+		os.Exit(1)
+	}
+
+	containerName := args[0]
+
+	if container.ValidSource(containerName) == false {
+		wwlog.Printf(wwlog.ERROR, "Unknown Warewulf container: %s\n", containerName)
+		os.Exit(1)
+	}
+
+	syscall.Mount("", "/", "", syscall.MS_PRIVATE, "")
+
+	containerPath := container.RootFsDir(containerName)
+
+	syscall.Chroot(containerPath)
+	os.Chdir("/")
+
+	syscall.Mount("rootfs", "rootfs", "", syscall.MS_BIND, "")
+	syscall.Mount("/proc", "/proc", "proc", 0, "")
+
+	ps1string := fmt.Sprintf("[%s] Warewulf> ", containerName)
+	os.Setenv("PS1", ps1string)
+
+	err := syscall.Exec(args[1], args[1:], os.Environ())
+	if err != nil {
+		wwlog.Printf(wwlog.ERROR, "%s\n", err)
+		os.Exit(1)
+	}
+
+	return nil
+}

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

@@ -0,0 +1,21 @@
+package child
+
+import "github.com/spf13/cobra"
+
+var (
+	baseCmd = &cobra.Command{
+		Use:    "__child",
+		Hidden: true,
+		RunE:   CobraRunE,
+		Args:   cobra.MinimumNArgs(1),
+	}
+)
+
+func init() {
+
+}
+
+// GetRootCommand returns the root cobra.Command for the application.
+func GetCommand() *cobra.Command {
+	return baseCmd
+}

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

@@ -0,0 +1,40 @@
+// +build linux
+
+package exec
+
+import (
+	"fmt"
+	"github.com/hpcng/warewulf/internal/pkg/container"
+	"github.com/hpcng/warewulf/internal/pkg/wwlog"
+	"github.com/spf13/cobra"
+	"os"
+	"os/exec"
+	"syscall"
+)
+
+func CobraRunE(cmd *cobra.Command, args []string) error {
+
+	containerName := args[0]
+
+	if container.ValidSource(containerName) == false {
+		wwlog.Printf(wwlog.ERROR, "Unknown Warewulf container: %s\n", containerName)
+		os.Exit(1)
+	}
+
+	c := exec.Command("/proc/self/exe", append([]string{"container", "exec", "__child"}, args...)...)
+
+	//c := exec.Command("/bin/sh")
+	c.SysProcAttr = &syscall.SysProcAttr{
+		Cloneflags: syscall.CLONE_NEWUTS | syscall.CLONE_NEWPID | syscall.CLONE_NEWNS,
+	}
+	c.Stdin = os.Stdin
+	c.Stdout = os.Stdout
+	c.Stderr = os.Stderr
+
+	if err := c.Run(); err != nil {
+		fmt.Println("ERROR", err)
+		os.Exit(1)
+	}
+
+	return nil
+}

internal/app/wwctl/container/exec/non-linux.go

@@ -0,0 +1,14 @@
+// +build !linux
+
+package exec
+
+import (
+	"github.com/hpcng/warewulf/internal/pkg/wwlog"
+	"github.com/spf13/cobra"
+)
+
+func CobraRunE(cmd *cobra.Command, args []string) error {
+	wwlog.Printf(wwlog.ERROR, "This command does not work on non-Linux hosts\n")
+
+	return nil
+}

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

@@ -0,0 +1,26 @@
+package exec
+
+import (
+	"github.com/hpcng/warewulf/internal/app/wwctl/container/exec/child"
+	"github.com/spf13/cobra"
+)
+
+var (
+	baseCmd = &cobra.Command{
+		Use:   "exec",
+		Short: "Spawn any command inside a Warewulf container",
+		Long:  "Run a command inside a Warewulf container ",
+		RunE:  CobraRunE,
+		Args:  cobra.MinimumNArgs(1),
+	}
+)
+
+func init() {
+	baseCmd.AddCommand(child.GetCommand())
+
+}
+
+// GetRootCommand returns the root cobra.Command for the application.
+func GetCommand() *cobra.Command {
+	return baseCmd
+}

internal/app/wwctl/container/root.go

@@ -2,6 +2,7 @@ package container
 
 import (
 	"github.com/hpcng/warewulf/internal/app/wwctl/container/build"
+	"github.com/hpcng/warewulf/internal/app/wwctl/container/exec"
 	"github.com/hpcng/warewulf/internal/app/wwctl/container/list"
 	"github.com/hpcng/warewulf/internal/app/wwctl/container/pull"
 	"github.com/spf13/cobra"
@@ -10,7 +11,7 @@ import (
 var (
 	baseCmd = &cobra.Command{
 		Use:   "container",
-		Short: "VNFS image management",
+		Short: "Container / VNFS image management",
 		Long:  "Virtual Node File System (VNFS) image management",
 	}
 	test bool
@@ -20,6 +21,7 @@ func init() {
 	baseCmd.AddCommand(build.GetCommand())
 	baseCmd.AddCommand(list.GetCommand())
 	baseCmd.AddCommand(pull.GetCommand())
+	baseCmd.AddCommand(exec.GetCommand())
 
 }