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Clean up ghw
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 - move the disk struct into types
 - move ghw mocker into its own subpackage so it can be reused

Signed-off-by: Itxaka <[email protected]>
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@Itxaka
Itxaka committed Sep 12, 2024
1 parent f312c84 commit 887ed47
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Showing 4 changed files with 178 additions and 171 deletions.
13 changes: 3 additions & 10 deletions ghw/ghw.go
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Original file line number Diff line number Diff line change
Expand Up @@ -17,13 +17,6 @@ const (
UNKNOWN = "unknown"
)

type Disk struct {
Name string `json:"name,omitempty" yaml:"name,omitempty"`
SizeBytes uint64 `json:"size_bytes,omitempty" yaml:"size_bytes,omitempty"`
UUID string `json:"uuid,omitempty" yaml:"uuid,omitempty"`
Partitions types.PartitionList `json:"partitions,omitempty" yaml:"partitions,omitempty"`
}

type Paths struct {
SysBlock string
RunUdevData string
Expand Down Expand Up @@ -56,12 +49,12 @@ func NewPaths(withOptionalPrefix string) *Paths {
return p
}

func GetDisks(paths *Paths, logger *types.KairosLogger) []*Disk {
func GetDisks(paths *Paths, logger *types.KairosLogger) []*types.Disk {
if logger == nil {
newLogger := types.NewKairosLogger("ghw", "info", false)
logger = &newLogger
}
disks := make([]*Disk, 0)
disks := make([]*types.Disk, 0)
logger.Logger.Debug().Str("path", paths.SysBlock).Msg("Scanning for disks")
files, err := os.ReadDir(paths.SysBlock)
if err != nil {
Expand All @@ -76,7 +69,7 @@ func GetDisks(paths *Paths, logger *types.KairosLogger) []*Disk {
// We don't care about unused loop devices...
continue
}
d := &Disk{
d := &types.Disk{
Name: dname,
SizeBytes: size,
UUID: diskUUID(paths, dname, "", logger),
Expand Down
168 changes: 7 additions & 161 deletions ghw/ghw_test.go
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Original file line number Diff line number Diff line change
@@ -1,15 +1,11 @@
package ghw_test

import (
"fmt"
"os"
"path/filepath"
"strconv"
"strings"
"testing"

"github.com/kairos-io/kairos-sdk/ghw"
"github.com/kairos-io/kairos-sdk/ghw/mocks"
"github.com/kairos-io/kairos-sdk/types"
"testing"

. "github.com/onsi/ginkgo/v2"
. "github.com/onsi/gomega"
Expand All @@ -21,16 +17,16 @@ func TestGHW(t *testing.T) {
}

var _ = Describe("GHW functions tests", func() {
var ghwMock GhwMock
var ghwMock mocks.GhwMock
BeforeEach(func() {
ghwMock = GhwMock{}
ghwMock = mocks.GhwMock{}
})
AfterEach(func() {
ghwMock.Clean()
})
Describe("With a disk", func() {
BeforeEach(func() {
mainDisk := ghw.Disk{
mainDisk := types.Disk{
Name: "disk",
UUID: "555",
SizeBytes: 1 * 1024,
Expand All @@ -51,7 +47,7 @@ var _ = Describe("GHW functions tests", func() {
})

It("Finds the disk and partition", func() {
disks := ghw.GetDisks(ghw.NewPaths(ghwMock.chroot), nil)
disks := ghw.GetDisks(ghw.NewPaths(ghwMock.Chroot), nil)
Expect(len(disks)).To(Equal(1), disks)
Expect(disks[0].Name).To(Equal("disk"), disks)
Expect(disks[0].UUID).To(Equal("555"), disks)
Expand All @@ -68,159 +64,9 @@ var _ = Describe("GHW functions tests", func() {
Describe("With no disks", func() {
It("Finds nothing", func() {
ghwMock.CreateDevices()
disks := ghw.GetDisks(ghw.NewPaths(ghwMock.chroot), nil)
disks := ghw.GetDisks(ghw.NewPaths(ghwMock.Chroot), nil)
Expect(len(disks)).To(Equal(0), disks)
})
})

})

// GhwMock is used to construct a fake disk to present to ghw when scanning block devices
// The way this works is ghw will use the existing files in the system to determine the different disks, partitions and
// mountpoints. It uses /sys/block, /proc/self/mounts and /run/udev/data to gather everything
// It also has an entrypoint to overwrite the root dir from which the paths are constructed so that allows us to override
// it easily and make it read from a different location.
// This mock is used to construct a fake FS with all its needed files on a different chroot and just add a Disk with its
// partitions and let the struct do its thing creating files and mountpoints and such
// You can even just pass no disks to simulate a system in which there is no disk/no cos partitions
type GhwMock struct {
chroot string
paths *ghw.Paths
disks []ghw.Disk
mounts []string
}

// AddDisk adds a disk to GhwMock
func (g *GhwMock) AddDisk(disk ghw.Disk) {
g.disks = append(g.disks, disk)
}

// AddPartitionToDisk will add a partition to the given disk and call Clean+CreateDevices, so we recreate all files
// It makes no effort checking if the disk exists
func (g *GhwMock) AddPartitionToDisk(diskName string, partition *types.Partition) {
for _, disk := range g.disks {
if disk.Name == diskName {
disk.Partitions = append(disk.Partitions, partition)
g.Clean()
g.CreateDevices()
}
}
}

// CreateDevices will create a new context and paths for ghw using the Chroot value as base, then set the env var GHW_ROOT so the
// ghw library picks that up and then iterate over the disks and partitions and create the necessary files
func (g *GhwMock) CreateDevices() {
d, _ := os.MkdirTemp("", "ghwmock")
g.chroot = d
g.paths = ghw.NewPaths(d)
// Create the /sys/block dir
_ = os.MkdirAll(g.paths.SysBlock, 0755)
// Create the /run/udev/data dir
_ = os.MkdirAll(g.paths.RunUdevData, 0755)
// Create only the /proc/ dir, we add the mounts file afterwards
procDir, _ := filepath.Split(g.paths.ProcMounts)
_ = os.MkdirAll(procDir, 0755)
for indexDisk, disk := range g.disks {
// For each dir we create the /sys/block/DISK_NAME
diskPath := filepath.Join(g.paths.SysBlock, disk.Name)
_ = os.Mkdir(diskPath, 0755)
// We create a dev file to indicate the devicenumber for a given disk
_ = os.WriteFile(filepath.Join(g.paths.SysBlock, disk.Name, "dev"), []byte(fmt.Sprintf("%d:0\n", indexDisk)), 0644)
// Also write the size
_ = os.WriteFile(filepath.Join(g.paths.SysBlock, disk.Name, "size"), []byte(strconv.FormatUint(disk.SizeBytes, 10)), 0644)
// Create the udevdata for this disk
_ = os.WriteFile(filepath.Join(g.paths.RunUdevData, fmt.Sprintf("b%d:0", indexDisk)), []byte(fmt.Sprintf("E:ID_PART_TABLE_UUID=%s\n", disk.UUID)), 0644)
for indexPart, partition := range disk.Partitions {
// For each partition we create the /sys/block/DISK_NAME/PARTITION_NAME
_ = os.Mkdir(filepath.Join(diskPath, partition.Name), 0755)
// Create the /sys/block/DISK_NAME/PARTITION_NAME/dev file which contains the major:minor of the partition
_ = os.WriteFile(filepath.Join(diskPath, partition.Name, "dev"), []byte(fmt.Sprintf("%d:6%d\n", indexDisk, indexPart)), 0644)
_ = os.WriteFile(filepath.Join(diskPath, partition.Name, "size"), []byte(fmt.Sprintf("%d\n", partition.Size)), 0644)
// Create the /run/udev/data/bMAJOR:MINOR file with the data inside to mimic the udev database
data := []string{fmt.Sprintf("E:ID_FS_LABEL=%s\n", partition.FilesystemLabel)}
if partition.FS != "" {
data = append(data, fmt.Sprintf("E:ID_FS_TYPE=%s\n", partition.FS))
}
if partition.UUID != "" {
data = append(data, fmt.Sprintf("E:ID_PART_ENTRY_UUID=%s\n", partition.UUID))
}
_ = os.WriteFile(filepath.Join(g.paths.RunUdevData, fmt.Sprintf("b%d:6%d", indexDisk, indexPart)), []byte(strings.Join(data, "")), 0644)
// If we got a mountpoint, add it to our fake /proc/self/mounts
if partition.MountPoint != "" {
// Check if the partition has a fs, otherwise default to ext4
if partition.FS == "" {
partition.FS = "ext4"
}
// Prepare the g.mounts with all the mount lines
g.mounts = append(
g.mounts,
fmt.Sprintf("%s %s %s ro,relatime 0 0\n", filepath.Join("/dev", partition.Name), partition.MountPoint, partition.FS))
}
}
}
// Finally, write all the mounts
_ = os.WriteFile(g.paths.ProcMounts, []byte(strings.Join(g.mounts, "")), 0644)
}

// RemoveDisk will remove the files for a disk. It makes no effort to check if the disk exists or not
func (g *GhwMock) RemoveDisk(disk string) {
// This could be simpler I think, just removing the /sys/block/DEVICE should make ghw not find anything and not search
// for partitions, but just in case do it properly
var newMounts []string
diskPath := filepath.Join(g.paths.SysBlock, disk)
_ = os.RemoveAll(diskPath)

// Try to find any mounts that match the disk given and remove them from the mounts
for _, mount := range g.mounts {
fields := strings.Fields(mount)
// If first field does not contain the /dev/DEVICE, add it to the newmounts
if !strings.Contains(fields[0], filepath.Join("/dev", disk)) {
newMounts = append(newMounts, mount)
}
}
g.mounts = newMounts
// Write the mounts again
_ = os.WriteFile(g.paths.ProcMounts, []byte(strings.Join(g.mounts, "")), 0644)
}

// RemovePartitionFromDisk will remove the files for a partition
// It makes no effort checking if the disk/partition/files exist
func (g *GhwMock) RemovePartitionFromDisk(diskName string, partitionName string) {
var newMounts []string
diskPath := filepath.Join(g.paths.SysBlock, diskName)
// Read the dev major:minor
devName, _ := os.ReadFile(filepath.Join(diskPath, partitionName, "dev"))
// Remove the MAJOR:MINOR file from the udev database
_ = os.RemoveAll(filepath.Join(g.paths.RunUdevData, fmt.Sprintf("b%s", devName)))
// Remove the /sys/block/DISK/PARTITION dir
_ = os.RemoveAll(filepath.Join(diskPath, partitionName))

// Try to find any mounts that match the partition given and remove them from the mounts
for _, mount := range g.mounts {
fields := strings.Fields(mount)
// If first field does not contain the /dev/PARTITION, add it to the newmounts
if !strings.Contains(fields[0], filepath.Join("/dev", partitionName)) {
newMounts = append(newMounts, mount)
}
}
g.mounts = newMounts
// Write the mounts again
_ = os.WriteFile(g.paths.ProcMounts, []byte(strings.Join(g.mounts, "")), 0644)
// Remove it from the partitions list
for index, disk := range g.disks {
if disk.Name == diskName {
var newPartitions types.PartitionList
for _, partition := range disk.Partitions {
if partition.Name != partitionName {
newPartitions = append(newPartitions, partition)
}
}
g.disks[index].Partitions = newPartitions
}
}
}

// Clean will remove the chroot dir and unset the env var
func (g *GhwMock) Clean() {
_ = os.RemoveAll(g.chroot)
}
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