Allow setting root to RW (#53)

This patch allows setting the root mount as RW indicated by setting
rd.cos.debugrw in the cmdline

Signed-off-by: Itxaka <itxaka.garcia@spectrocloud.com>

internal/cmd/commands.go

@@ -43,34 +43,26 @@ Sends a generic event payload with the configuration found in the scanned direct
 			v := version.Get()
 			log.Logger.Info().Str("commit", v.GitCommit).Str("compiled with", v.GoVersion).Str("version", v.Version).Msg("Immucore")
 
+			cmdline, _ := os.ReadFile("/proc/cmdline")
+			log.Logger.Debug().Msg(string(cmdline))
 			g := herd.DAG(herd.EnableInit)
 
-			// You can pass rd.cos.disable in the cmdline to disable the whole immutable stuff
-			cosDisable := len(utils.ReadCMDLineArg("rd.cos.disable")) > 0
-
-			img := utils.ReadCMDLineArg("cos-img/filename=")
-			if len(img) == 0 {
-				// If we boot from LIVE media or are using dry-run, we use a fake img as we still want to do things
-				if c.Bool("dry-run") || cosDisable {
-					img = []string{"fake"}
-				} else {
-					log.Logger.Fatal().Msg("Could not get the image name from cmdline (i.e. cos-img/filename=/cOS/active.img)")
-				}
-			}
-			log.Debug().Strs("TargetImage", img).Msg("Target image")
+			// Get targets and state
+			targetLabel, targetDevice := utils.GetTarget(c.Bool("dry-run"))
 
 			s := &mount.State{
-				Logger:      log.Logger,
-				Rootdir:     utils.GetRootDir(),
-				MountRoot:   true,
-				TargetLabel: utils.BootStateToLabel(),
-				TargetImage: img[0],
+				Logger:        log.Logger,
+				Rootdir:       utils.GetRootDir(),
+				TargetLabel:   targetDevice,
+				TargetImage:   targetLabel,
+				RootMountMode: utils.RootRW(),
 			}
 
-			if cosDisable {
-				log.Logger.Info().Msg("Stanza rd.cos.disable on the cmdline.")
+			if utils.DisableImmucore() {
+				log.Logger.Info().Msg("Stanza rd.cos.disable on the cmdline or booting from CDROM/Netboot/recovery. Disabling immucore.")
 				err = s.RegisterLiveMedia(g)
 			} else {
+				log.Logger.Info().Msg("Booting on active/passive.")
 				err = s.RegisterNormalBoot(g)
 			}
 
@@ -81,6 +73,7 @@ Sends a generic event payload with the configuration found in the scanned direct
 
 			log.Info().Msg(s.WriteDAG(g))
 
+			// Once we print the dag we can exit already
 			if c.Bool("dry-run") {
 				return nil
 			}

internal/utils/common.go

@@ -3,6 +3,7 @@ package utils
 import (
 	"github.com/joho/godotenv"
 	"github.com/kairos-io/kairos/sdk/state"
+	"github.com/rs/zerolog/log"
 	"os"
 	"strings"
 )
@@ -18,8 +19,6 @@ func BootStateToLabel() string {
 		return "COS_ACTIVE"
 	case "passive_boot":
 		return "COS_PASSIVE"
-	case "recovery_boot":
-		return "COS_SYSTEM"
 	default:
 		return ""
 	}
@@ -108,3 +107,44 @@ func CleanupSlice(slice []string) []string {
 	}
 	return cleanSlice
 }
+
+// GetTarget gets the target image and device to mount in /sysroot
+func GetTarget(dryRun bool) (string, string) {
+	var img, label string
+
+	label = BootStateToLabel()
+
+	// If dry run, or we are disabled return whatever values, we won't go much further
+	if dryRun || DisableImmucore() {
+		return "fake", label
+	}
+
+	img = ReadCMDLineArg("cos-img/filename=")[0]
+
+	// If no image just panic here, we cannot longer continue
+	if img == "" {
+		log.Logger.Fatal().Msg("Could not get the image name from cmdline (i.e. cos-img/filename=/cOS/active.img)")
+	}
+
+	log.Debug().Str("what", img).Msg("Target device")
+	log.Debug().Str("what", label).Msg("Target label")
+	return img, label
+}
+
+// DisableImmucore identifies if we need to be disabled
+// We disable if we boot from CD, netboot, recovery or have the rd.cos.disable stanza in cmdline
+func DisableImmucore() bool {
+	cmdline, _ := os.ReadFile("/proc/cmdline")
+	cmdlineS := string(cmdline)
+
+	return strings.Contains(cmdlineS, "live:LABEL") || strings.Contains(cmdlineS, "live:CDLABEL") || strings.Contains(cmdlineS, "netboot") || strings.Contains(cmdlineS, "rd.cos.disable")
+}
+
+// RootRW tells us if the mode to mount root
+func RootRW() string {
+	if len(ReadCMDLineArg("rd.cos.debugrw")) > 0 {
+		log.Logger.Warn().Msg("Mounting root as RW")
+		return "rw"
+	}
+	return "ro"
+}

pkg/mount/dag_steps.go

@@ -33,22 +33,16 @@ func (s *State) MountRootDagStep(g *herd.Graph) error {
 	if err != nil {
 		s.Logger.Debug().Err(err).Msg("runtime")
 	}
-	stateName := runtime.State.Name
-	stateFs := runtime.State.Type
-	// Recovery is a different partition
-	if internalUtils.IsRecovery() {
-		stateName = runtime.Recovery.Name
-		stateFs = runtime.Recovery.Type
-	}
+
 	// 1 - mount the state partition to find the images (active/passive/recovery)
 	err = g.Add(cnst.OpMountState,
 		herd.WithCallback(
 			s.MountOP(
-				stateName,
+				runtime.State.Name,
 				s.path("/run/initramfs/cos-state"),
-				stateFs,
+				runtime.State.Type,
 				[]string{
-					"ro", // or rw
+					s.RootMountMode,
 				}, 60*time.Second),
 		),
 	)
@@ -74,8 +68,9 @@ func (s *State) MountRootDagStep(g *herd.Graph) error {
 				// On some systems the COS_ACTIVE/PASSIVE label is automatically shown as soon as we mount the device
 				// But on other it seems like it won't trigger which causes the sysroot to not be mounted as we cant find
 				// the block device by the target label. Make sure we run this after mounting so we refresh the devices.
-				sh, _ := utils.SH("udevadm trigger --settle")
+				sh, _ := utils.SH("udevadm trigger")
 				s.Logger.Debug().Str("output", sh).Msg("udevadm trigger")
+				log.Logger.Debug().Str("targetImage", s.TargetImage).Str("path", s.Rootdir).Str("TargetLabel", s.TargetLabel).Msg("mount done")
 				return err
 			},
 		))
@@ -93,7 +88,7 @@ func (s *State) MountRootDagStep(g *herd.Graph) error {
 				s.Rootdir,
 				"ext4", // are images always ext2?
 				[]string{
-					"ro", // or rw
+					s.RootMountMode,
 					"suid",
 					"dev",
 					"exec",

pkg/mount/state.go

@@ -19,19 +19,19 @@ import (
 )
 
 type State struct {
-	Logger      zerolog.Logger
-	Rootdir     string // e.g. /sysroot inside initrd with pivot, / with nopivot
-	TargetImage string // e.g. /cOS/active.img
-	TargetLabel string // e.g. COS_ACTIVE
+	Logger        zerolog.Logger
+	Rootdir       string // where to mount the root partition e.g. /sysroot inside initrd with pivot, / with nopivot
+	TargetImage   string // image from the state partition to mount as loop device e.g. /cOS/active.img
+	TargetLabel   string //  e.g. COS_ACTIVE
+	RootMountMode string // How to mount the root partition e.g. ro or rw
 
 	// /run/cos-layout.env (different!)
 	OverlayDirs  []string          // e.g. /var
 	BindMounts   []string          // e.g. /etc/kubernetes
 	CustomMounts map[string]string // e.g. diskid : mountpoint
 
-	StateDir  string // e.g. "/usr/local/.state"
-	MountRoot bool   // e.g. if true, it tries to find the image to loopback mount
-	fstabs    []*fstab.Mount
+	StateDir string // e.g. "/usr/local/.state"
+	fstabs   []*fstab.Mount
 }
 
 func (s *State) path(p ...string) string {

pkg/mount/state_test.go

@@ -28,7 +28,6 @@ var _ = Describe("mounting immutable setup", func() {
 				Rootdir:     "/",
 				TargetImage: "/cOS/myimage.img",
 				TargetLabel: "COS_LABEL",
-				MountRoot:   true,
 			}
 
 			err := s.RegisterNormalBoot(g)
@@ -40,7 +39,7 @@ var _ = Describe("mounting immutable setup", func() {
 
 		})
 		It("generates normal dag with extra dirs", func() {
-			s := &mount.State{Rootdir: "/", MountRoot: true,
+			s := &mount.State{Rootdir: "/",
 				OverlayDirs:  []string{"/etc"},
 				BindMounts:   []string{"/etc/kubernetes"},
 				CustomMounts: map[string]string{"COS_PERSISTENT": "/usr/local"}}