Fixed hardcoded root partition device name sda2

The root partition may not be /dev/sda2, for example if set the boot disk as the
second disk, the root partition device name will be /dev/sdb2. It may be
/dev/vda2 if not using san disk. The fix figured out the root partition device
UUID and set the UUID as the root, the root partition device UUID keeps no
change.

Signed-off-by: JUN JIE NAN <[email protected]>

Author: nanjj

distrobuilder/main_incus.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"context"
 	"errors"
 	"fmt"
 	"io"
@@ -401,6 +402,13 @@ func (c *cmdIncus) run(cmd *cobra.Command, args []string, overlayDir string) err
 
 	c.global.logger.WithField("trigger", "post-files").Info("Running hooks")
 
+	// actionCtx := context.WithValue(c.global.ctx)
+	actionEnviron := []string{}
+	if rootfsDevUUID, err := vm.findRootfsDevUUID(); err != nil {
+		return err
+	} else {
+		actionEnviron = append(actionEnviron, fmt.Sprintf("ROOTFS_DEVICE_UUID=%s", rootfsDevUUID))
+	}
 	// Run post files hook
 	for _, action := range c.global.definition.GetRunnableActions("post-files", imageTargets) {
 		if action.Pongo {
@@ -410,7 +418,8 @@ func (c *cmdIncus) run(cmd *cobra.Command, args []string, overlayDir string) err
 			}
 		}
 
-		err := shared.RunScript(c.global.ctx, action.Action)
+		err := shared.RunScript(context.WithValue(c.global.ctx, "environ", actionEnviron),
+			action.Action)
 		if err != nil {
 			{
 				err := exitChroot()

distrobuilder/vm.go

@@ -61,6 +61,31 @@ func (v *vm) getUEFIDevFile() string {
 	return fmt.Sprintf("%sp1", v.loopDevice)
 }
 
+func (v *vm) findRootfsDevUUID() (rootUUID string, err error) {
+	rootfsDevFile := v.getRootfsDevFile()
+	if rootfsDevFile == "" {
+		err = fmt.Errorf("Failed to get rootfs device name.")
+		return
+	}
+	var out strings.Builder
+	if err = shared.RunCommand(v.ctx, nil, &out, "blkid", "-o", "export", rootfsDevFile); err != nil {
+		err = fmt.Errorf("Failed to get rootfs device UUID: %w", err)
+		return
+	}
+	fields := strings.Fields(out.String())
+	for _, field := range fields {
+		if strings.HasPrefix(field, "UUID") {
+			rootUUID = field
+			break
+		}
+	}
+	if rootUUID == "" {
+		err = fmt.Errorf("No rootfs device UUID found")
+		return
+	}
+	return
+}
+
 func (v *vm) createEmptyDiskImage() error {
 	f, err := os.Create(v.imageFile)
 	if err != nil {

doc/examples/ubuntu.yaml

@@ -322,7 +322,7 @@ actions:
     update-grub
     grub-install --uefi-secure-boot --target="${TARGET}-efi" --no-nvram --removable
     update-grub
-    sed -i "s#root=[^ ]*#root=/dev/sda2#g" /boot/grub/grub.cfg
+    sed -e "s#root=[^ ]*#root=${ROOTFS_DEVICE_UUID}#g" -i /boot/grub/grub.cfg
   types:
   - vm
 

shared/util.go

@@ -56,6 +56,9 @@ func Copy(src, dest string) error {
 // RunCommand runs a command. Stdout is written to the given io.Writer. If nil, it's written to the real stdout. Stderr is always written to the real stderr.
 func RunCommand(ctx context.Context, stdin io.Reader, stdout io.Writer, name string, arg ...string) error {
 	cmd := exec.CommandContext(ctx, name, arg...)
+	if env, ok := ctx.Value("environ").([]string); ok && len(env) > 0 {
+		cmd.Env = append(os.Environ(), env...)
+	}
 
 	if stdin != nil {
 		cmd.Stdin = stdin