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feat:[close #159] make use of systemd mount units
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This is cleaner than using a mount script and running this as a service.
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@taukakao
taukakao authored Dec 13, 2023
1 parent 24951bc commit 891f94a
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Showing 2 changed files with 77 additions and 93 deletions.
6 changes: 6 additions & 0 deletions core/disk-manager.go
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Original file line number Diff line number Diff line change
Expand Up @@ -19,6 +19,7 @@ import (
"fmt"
"os"
"os/exec"
"strings"
"syscall"
)

Expand Down Expand Up @@ -210,3 +211,8 @@ func (p *Partition) Unmount() error {
func (p *Partition) IsDevMapper() bool {
return p.Parent != nil
}

// IsEncrypted returns whether the partition is encrypted
func (p *Partition) IsEncrypted() bool {
return strings.HasPrefix(p.Device, "luks-")
}
164 changes: 71 additions & 93 deletions core/system.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -47,10 +47,7 @@ const (
)

const (
MountScriptPath = "/usr/sbin/.abroot-mountpoints"
MountUnitDir = "/etc/systemd/system"
SystemDTargetDir = "/etc/systemd/system/%s.target.wants"
MountUnitFile = "/abroot-mount.service"
MountUnitDir = "/etc/systemd/system"
)

type ABSystemOperation string
Expand Down Expand Up @@ -315,14 +312,24 @@ func (s *ABSystem) GenerateFstab(rootPath string, root ABRootPartition) error {
#
# <file system> <mount point> <type> <options> <dump> <pass>
UUID=%s / %s defaults 0 0
/.system/usr /.system/usr none bind,ro
%s /var auto defaults 0 0
`
varSource := ""
if s.RootM.VarPartition.IsDevMapper() {
varSource = fmt.Sprintf("/dev/mapper/%s", s.RootM.VarPartition.Device)
} else {
varSource = fmt.Sprintf("-U %s", s.RootM.VarPartition.Uuid)
}

fstab := fmt.Sprintf(
template,
root.Partition.Uuid,
root.Partition.FsType,
varSource,
)

err := os.WriteFile(rootPath+"/etc/fstab", []byte(fstab), 0644)
err := os.WriteFile(filepath.Join(rootPath, "/etc/fstab"), []byte(fstab), 0644)
if err != nil {
PrintVerbose("ABSystem.GenerateFstab:err: %s", err)
return err
Expand Down Expand Up @@ -382,100 +389,77 @@ func (s *ABSystem) GenerateCrypttab(rootPath string) error {
return nil
}

// GenerateMountpointsScript generates a /usr/sbin/.abroot-mountpoints file for the future root
func (s *ABSystem) GenerateMountpointsScript(rootPath string, root ABRootPartition) error {
PrintVerbose("ABSystem.GenerateMountpointsScript: generating script")

template := `#!/usr/bin/bash
echo "ABRoot: Initializing mount points..."
# /var mount
mount %s /var
# /etc overlay
mount -t overlay overlay -o lowerdir=/.system/etc,upperdir=/var/lib/abroot/etc/%s,workdir=/var/lib/abroot/etc/%s-work /etc
// GenerateSystemdUnits generates systemd units that mount the mutable parts of the system
func (s *ABSystem) GenerateSystemdUnits(rootPath string, root ABRootPartition) error {
PrintVerbose("ABSystem.GenerateSystemdUnits: generating units")

# /var binds
mount -o bind /var/home /home
mount -o bind /var/opt /opt
mount -o bind,ro /.system/usr /usr
mount -o bind /var/lib/abroot/etc/%s/locales /usr/lib/locale
`
mountExtCmd := ""
if s.RootM.VarPartition.IsDevMapper() {
mountExtCmd = fmt.Sprintf("/dev/mapper/%s", s.RootM.VarPartition.Device)
} else {
mountExtCmd = fmt.Sprintf("-U %s", s.RootM.VarPartition.Uuid)
extraDepends := ""
if root.Partition.IsEncrypted() || s.RootM.VarPartition.IsEncrypted() {
extraDepends = "cryptsetup.target"
}
mountpoints := fmt.Sprintf(template, mountExtCmd, root.Label, root.Label, root.Label)

err := os.WriteFile(rootPath+MountScriptPath, []byte(mountpoints), 0755)
if err != nil {
PrintVerbose("ABSystem.GenerateMountpointsScript:err(3): %s", err)
return err
type varmount struct {
source string
destination string
fsType string
options string
}

err = os.Chmod(rootPath+MountScriptPath, 0755)
if err != nil {
PrintVerbose("ABSystem.GenerateMountpointsScript:err(4): %s", err)
return err
mounts := []varmount{
{"/var/home", "/home", "none", "bind"},
{"/var/opt", "/opt", "none", "bind"},
{"/var/lib/abroot/etc/" + root.Label + "/locales", "/.system/usr/lib/locale", "none", "bind"},
{"overlay", "/.system/etc", "overlay", "lowerdir=/.system/etc,upperdir=/var/lib/abroot/etc/" + root.Label + ",workdir=/var/lib/abroot/etc/" + root.Label + "-work"},
}

PrintVerbose("ABSystem.GenerateMountpointsScript: script generated")
return nil
}
afterVarTemplate := `[Unit]
Description=Mounts %s from var
After=local-fs-pre.target %s
Before=local-fs.target nss-user-lookup.target
RequiresMountsFor=/var
// GenerateMountpointsSystemDUnit creates a SystemD unit to setup the /var partition and its
// derivatives such as /home, /opt, and /etc.
// This unit must run as soon as all encrypted partitions (if any) have been decrupted.
func (s *ABSystem) GenerateMountpointsSystemDUnit(rootPath string, root ABRootPartition) error {
PrintVerbose("ABSystem.GenerateMountpointsSystemDUnit: generating script")

depTarget := "local-fs"
template := `[Unit]
Description=Mount partitions
Requires=%s.target
After=%s.target
Before=nss-user-lookup.target
[Service]
Type=oneshot
ExecStart=%s
[Mount]
What=%s
Where=%s
Type=%s
Options=%s
`
// Check for encrypted roots
for _, rootDevice := range s.RootM.Partitions {
if strings.HasPrefix(rootDevice.Partition.Device, "luks-") {
depTarget = "cryptsetup"
break
}
}

// Check for encrypted var
if strings.HasPrefix(s.RootM.VarPartition.Device, "luks-") {
depTarget = "cryptsetup"
}
for _, mount := range mounts {
PrintVerbose("ABSystem.GenerateSystemdUnits: generating unit for %s", mount.destination)

unit := fmt.Sprintf(template, depTarget, depTarget, MountScriptPath)
unit := fmt.Sprintf(afterVarTemplate, mount.destination, extraDepends, mount.source, mount.destination, mount.fsType, mount.options)

err := os.WriteFile(rootPath+MountUnitDir+MountUnitFile, []byte(unit), 0755)
if err != nil {
PrintVerbose("ABSystem.GenerateMountpointsSystemDUnit:err(2): %s", err)
return err
}
// the unit file needs to have the escaped mount point as its name
out, err := exec.Command("systemd-escape", "--path", mount.destination).Output()
if err != nil {
PrintVerbose("ABSystem.GenerateSystemdUnits:err(1): failed to determine escaped path: %s", err)
return err
}
mountUnitFile := "/" + strings.Replace(string(out), "\n", "", -1) + ".mount"

err = os.MkdirAll(rootPath+fmt.Sprintf(SystemDTargetDir, depTarget), 0755)
if err != nil {
PrintVerbose("ABSystem.GenerateMountpointsSystemDUnit:err(3): %s", err)
return err
}
err = os.WriteFile(filepath.Join(rootPath, MountUnitDir, mountUnitFile), []byte(unit), 0644)
if err != nil {
PrintVerbose("ABSystem.GenerateSystemdUnits:err(2): %s", err)
return err
}

err = os.Symlink(".."+MountUnitFile, rootPath+fmt.Sprintf(SystemDTargetDir, depTarget)+MountUnitFile)
if err != nil {
PrintVerbose("ABSystem.GenerateMountpointsSystemDUnit:err(4): %s", err)
return err
const targetWants string = "/local-fs.target.wants"

err = os.MkdirAll(filepath.Join(rootPath, MountUnitDir, targetWants), 0755)
if err != nil {
PrintVerbose("ABSystem.GenerateSystemdUnits:err(3): %s", err)
return err
}

err = os.Symlink(filepath.Join("../", mountUnitFile), filepath.Join(rootPath, MountUnitDir, targetWants, mountUnitFile))
if err != nil {
PrintVerbose("ABSystem.GenerateSystemdUnits:err(4): failed to create symlink: %s", err)
return err
}
}

PrintVerbose("ABSystem.GenerateMountpointsSystemDUnit: unit generated")
PrintVerbose("ABSystem.GenerateSystemdUnits: units generated")
return nil
}

Expand Down Expand Up @@ -707,8 +691,8 @@ func (s *ABSystem) RunOperation(operation ABSystemOperation) error {
return err
}

// Stage 6: Generate /etc/fstab, /etc/crypttab, /usr/sbin/.abroot-mountpoints, and the
// SystemD unit to setup mountpoints
// Stage 6: Generate /etc/fstab, /etc/crypttab, and the
// SystemD units to setup mountpoints
// ------------------------------------------------
PrintVerbose("[Stage 6] -------- ABSystemRunOperation")

Expand All @@ -724,15 +708,9 @@ func (s *ABSystem) RunOperation(operation ABSystemOperation) error {
return err
}

err = s.GenerateMountpointsScript(systemNew, partFuture)
if err != nil {
PrintVerbose("ABSystem.RunOperation:err(6.2): %s", err)
return err
}

err = s.GenerateMountpointsSystemDUnit(systemNew, partFuture)
err = s.GenerateSystemdUnits(systemNew, partFuture)
if err != nil {
PrintVerbose("ABSystem.RunOperation:err(6.3): %s", err)
PrintVerbose("ABSystem.RunOperation:err(6.2): Failed to Generate SystemdUnits: %s", err)
return err
}

Expand Down

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