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Revert "Atomic overlay file application in wwclient"

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This reverts commit 9f11b4a2b9.
This commit is contained in:
Christian Goll
2025-08-13 09:57:31 +02:00
parent ecced2399a
commit 1e54d02f70
5 changed files with 41 additions and 296 deletions
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293
internal/app/wwclient/root.go
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@@ -1,8 +1,8 @@
package wwclient
import (
"errors"
"fmt"
"io"
"net"
"net/http"
"net/url"
@@ -10,7 +10,6 @@ import (
"os/exec"
"os/signal"
"path"
"path/filepath"
"strings"
"syscall"
"time"
@@ -33,7 +32,6 @@ var (
SilenceUsage: true,
Args: cobra.NoArgs,
}
Once bool
DebugFlag bool
PIDFile string
Webclient *http.Client
@@ -41,7 +39,6 @@ var (
)
func init() {
rootCmd.PersistentFlags().BoolVar(&Once, "once", false, "Run once and exit")
rootCmd.PersistentFlags().BoolVarP(&DebugFlag, "debug", "d", false, "Run with debugging messages enabled.")
rootCmd.PersistentFlags().StringVarP(&PIDFile, "pidfile", "p", "/var/run/wwclient.pid", "PIDFile to use")
rootCmd.PersistentFlags().StringVar(&WarewulfConfArg, "warewulfconf", "", "Set the warewulf configuration file")
@@ -55,12 +52,6 @@ func GetRootCommand() *cobra.Command {
}
func CobraRunE(cmd *cobra.Command, args []string) (err error) {
if DebugFlag {
wwlog.SetLogLevel(wwlog.DEBUG)
} else {
wwlog.SetLogLevel(wwlog.INFO)
}
conf := warewulfconf.Get()
if WarewulfConfArg != "" {
err = conf.Read(WarewulfConfArg, false)
@@ -73,29 +64,33 @@ func CobraRunE(cmd *cobra.Command, args []string) (err error) {
return
}
pid, err := pidfile.Write(PIDFile)
if err != nil {
if pid > 0 { // wwclient is already running
return fmt.Errorf("%v: not starting", err)
} else { // the pidfile is stale
wwlog.Warn("%s: starting new wwclient", err)
}
}
defer cleanUp()
if err != nil && pid == -1 {
wwlog.Warn("%v. starting new wwclient", err)
} else if err != nil && pid > 0 {
return errors.New("found pidfile " + PIDFile + " not starting")
}
target := "/"
if os.Args[0] == path.Join(conf.Paths.WWClientdir, "wwclient") {
err := os.Chdir("/")
if err != nil {
return fmt.Errorf("failed to change dir: %w", err)
}
wwlog.Warn("updating live file system: cancel now if this is in error")
time.Sleep(5000 * time.Millisecond)
} else {
target = "/warewulf/wwclient-test"
fmt.Printf("Called via: %s\n", os.Args[0])
fmt.Printf("Runtime overlay is being put in '%s' rather than '/'\n", target)
fmt.Printf("Runtime overlay is being put in '/warewulf/wwclient-test' rather than '/'\n")
fmt.Printf("For full functionality call with: %s\n", path.Join(conf.Paths.WWClientdir, "wwclient"))
err := os.MkdirAll(target, 0755)
err := os.MkdirAll("/warewulf/wwclient-test", 0755)
if err != nil {
return fmt.Errorf("failed to create dir: %w", err)
}
err = os.Chdir("/warewulf/wwclient-test")
if err != nil {
return fmt.Errorf("failed to change dir: %w", err)
}
}
localTCPAddr := net.TCPAddr{}
@@ -151,18 +146,19 @@ func CobraRunE(cmd *cobra.Command, args []string) (err error) {
tag = "Unknown"
}
wwlog.Debug("uuid: %s", localUUID.String())
wwlog.Debug("assetkey: %s", tag)
cmdline, err := os.ReadFile("/proc/cmdline")
if err != nil {
return fmt.Errorf("could not read from /proc/cmdline: %w", err)
}
wwid, err := parseWWIDFromCmdline(string(cmdline))
if err != nil {
return fmt.Errorf("failed to parse wwid: %w", err)
wwid_tmp := strings.Split(string(cmdline), "wwid=")
if len(wwid_tmp) < 2 {
return fmt.Errorf("'wwid' is not defined in /proc/cmdline")
}
wwid := strings.Split(wwid_tmp[1], " ")[0]
wwid = strings.TrimSuffix(wwid, "\n")
// Dereference wwid from [interface] for cases that cannot have /proc/cmdline set by bootloader
if string(wwid[0]) == "[" {
iface := wwid[1 : len(wwid)-1]
@@ -174,8 +170,6 @@ func CobraRunE(cmd *cobra.Command, args []string) (err error) {
wwlog.Info("Dereferencing wwid from [%s] to %s", iface, wwid)
}
wwlog.Debug("wwid: %s", wwid)
duration := 300
if conf.Warewulf.UpdateInterval > 0 {
duration = conf.Warewulf.UpdateInterval
@@ -184,10 +178,6 @@ func CobraRunE(cmd *cobra.Command, args []string) (err error) {
// listen on SIGHUP
sigs := make(chan os.Signal, 1)
signal.Notify(sigs, syscall.SIGHUP, syscall.SIGTERM, syscall.SIGINT)
// Add a channel to signal main loop to exit gracefully
exitChan := make(chan bool, 1)
go func() {
for {
sig := <-sigs
@@ -198,9 +188,7 @@ func CobraRunE(cmd *cobra.Command, args []string) (err error) {
stopTimer.Reset(0)
case syscall.SIGTERM, syscall.SIGINT:
wwlog.Info("terminating wwclient, %v", sig)
// Signal main loop to exit instead of calling os.Exit(0)
exitChan <- true
return
os.Exit(0)
}
}
}()
@@ -209,50 +197,20 @@ func CobraRunE(cmd *cobra.Command, args []string) (err error) {
if ipaddr == "" {
ipaddr = conf.Ipaddr
}
for {
updateSystem(target, ipaddr, conf.Warewulf.Port, wwid, tag, localUUID)
updateSystem(ipaddr, conf.Warewulf.Port, wwid, tag, localUUID)
if !finishedInitialSync {
// Notify systemd that the service has started successfully.
//
// Ignoring error and status, as this wouldn't change anything.
// ignore error and status here, as this wouldn't change anything
_, _ = daemon.SdNotify(false, daemon.SdNotifyReady)
finishedInitialSync = true
}
if Once {
return nil
}
// Check for exit signal or timer
select {
case <-exitChan:
wwlog.Info("gracefully shutting down")
return nil
case <-stopTimer.C:
stopTimer.Reset(time.Duration(duration) * time.Second)
}
<-stopTimer.C
stopTimer.Reset(time.Duration(duration) * time.Second)
}
}
// parseWWIDFromCmdline extracts the wwid parameter from kernel command line
func parseWWIDFromCmdline(cmdline string) (string, error) {
params := strings.Fields(cmdline)
for _, param := range params {
if strings.HasPrefix(param, "wwid=") {
wwid := strings.TrimPrefix(param, "wwid=")
if wwid == "" {
return "", fmt.Errorf("wwid parameter is empty")
}
return wwid, nil
}
}
return "", fmt.Errorf("wwid parameter not found in kernel command line")
}
func updateSystem(target string, ipaddr string, port int, wwid string, tag string, localUUID uuid.UUID) {
func updateSystem(ipaddr string, port int, wwid string, tag string, localUUID uuid.UUID) {
var resp *http.Response
counter := 0
for {
@@ -288,200 +246,13 @@ func updateSystem(target string, ipaddr string, port int, wwid string, tag strin
time.Sleep(60000 * time.Millisecond)
return
}
wwlog.Info("applying runtime overlay")
// unpack overlay into a temporary directory
tempDir, err := os.MkdirTemp("", "wwclient-")
if err != nil {
wwlog.Error("failed to create temp directory: %s", err)
return
}
defer os.RemoveAll(tempDir)
wwlog.Debug("unpacking runtime overlay to %s", tempDir)
command := exec.Command("/bin/sh", "-c", fmt.Sprintf("gzip -dc | cpio -iu --directory=%s", tempDir))
command := exec.Command("/bin/sh", "-c", "gzip -dc | cpio -iu")
command.Stdin = resp.Body
err = command.Run()
err := command.Run()
if err != nil {
wwlog.Error("failed running cpio: %s", err)
return
}
// Atomically move files from temp directory to current working directory
err = atomicApplyOverlay(tempDir, target)
if err != nil {
wwlog.Error("failed to apply overlay: %s", err)
}
}
func atomicApplyOverlay(srcDir, destDir string) error {
return filepath.Walk(srcDir, func(srcPath string, info os.FileInfo, err error) error {
if err != nil {
return err
}
// Calculate relative path from srcDir
relPath, err := filepath.Rel(srcDir, srcPath)
if err != nil {
return err
}
// Skip the root directory itself
if relPath == "." {
return nil
}
destPath := filepath.Join(destDir, relPath)
if info.IsDir() {
// Create directory if it doesn't exist
wwlog.Debug("Ensuring directory exists: %s", destPath)
err := os.MkdirAll(destPath, info.Mode())
if err != nil {
return err
}
// Ensure permissions are updated even if directory already existed
wwlog.Debug("Updating permissions for directory: %s", destPath)
err = os.Chmod(destPath, info.Mode())
if err != nil {
return fmt.Errorf("failed to update directory permissions for %s: %w", destPath, err)
}
// Update ownership and timestamps
if stat, ok := info.Sys().(*syscall.Stat_t); ok {
wwlog.Debug("Updating ownership for directory: %s", destPath)
err := os.Chown(destPath, int(stat.Uid), int(stat.Gid))
if err != nil {
wwlog.Warn("failed to update ownership for directory %s: %s", destPath, err)
}
}
err = os.Chtimes(destPath, info.ModTime(), info.ModTime())
if err != nil {
wwlog.Warn("failed to update timestamps for directory %s: %s", destPath, err)
}
return nil
} else if info.Mode()&os.ModeSymlink != 0 {
// Handle symbolic links
linkTarget, err := os.Readlink(srcPath)
if err != nil {
return fmt.Errorf("failed to read symlink %s: %w", srcPath, err)
}
// Create a temporary symlink in same directory as the destination.
// This ensures the temp file is on the same filesystem as the final
// destination, so the rename placement is atomic.
destParent := filepath.Dir(destPath)
// Ensure destination directory exists
if err := os.MkdirAll(destParent, 0755); err != nil {
return fmt.Errorf("failed to create destination directory %s: %w", destParent, err)
}
tempFile, err := os.CreateTemp(destParent, ".wwclient-tmp-")
if err != nil {
return fmt.Errorf("failed to create temp file for symlink %s: %w", destPath, err)
}
tempPath := tempFile.Name()
_ = tempFile.Close()
os.Remove(tempPath) // Remove the regular file so we can create a symlink
wwlog.Debug("Creating temporary symlink: %s -> %s", tempPath, linkTarget)
err = os.Symlink(linkTarget, tempPath)
if err != nil {
return fmt.Errorf("failed to create temporary symlink %s: %w", tempPath, err)
}
// Update ownership if possible (note: lchown for symlinks)
if stat, ok := info.Sys().(*syscall.Stat_t); ok {
wwlog.Debug("Updating ownership for temporary symlink: %s", tempPath)
err := syscall.Lchown(tempPath, int(stat.Uid), int(stat.Gid))
if err != nil {
wwlog.Warn("failed to update ownership for temporary symlink %s: %s", tempPath, err)
}
}
// Atomic rename - this will be atomic since both files are in the same directory
wwlog.Debug("Moving symlink %s to %s", tempPath, destPath)
err = os.Rename(tempPath, destPath)
if err != nil {
os.Remove(tempPath)
return fmt.Errorf("failed to atomically move symlink %s to %s: %w", tempPath, destPath, err)
}
return nil
} else {
// Create a temporary file in same directory as the destination.
// This ensures the temp file is on the same filesystem as the final
// destination, so the rename placement is atomic.
destParent := filepath.Dir(destPath)
// Ensure destination directory exists
if err := os.MkdirAll(destParent, 0755); err != nil {
return fmt.Errorf("failed to create destination directory %s: %w", destParent, err)
}
tempFile, err := os.CreateTemp(destParent, ".wwclient-tmp-")
if err != nil {
return fmt.Errorf("failed to create temp file for %s: %w", destPath, err)
}
tempPath := tempFile.Name()
_ = tempFile.Close()
// Copy file content and metadata
wwlog.Debug("Copying file from %s to temp location %s", srcPath, tempPath)
err = copyFile(srcPath, tempPath, info)
if err != nil {
os.Remove(tempPath)
return fmt.Errorf("failed to copy %s to temp location: %w", srcPath, err)
}
// Atomic rename - this will be atomic since both files are in the same directory
// (and thus on the same filesystem)
wwlog.Debug("Moving %s to %s", tempPath, destPath)
err = os.Rename(tempPath, destPath)
if err != nil {
os.Remove(tempPath)
return fmt.Errorf("failed to atomically move %s to %s: %w", tempPath, destPath, err)
}
}
return nil
})
}
func copyFile(src, dst string, srcInfo os.FileInfo) error {
srcFile, err := os.Open(src)
if err != nil {
return err
}
defer srcFile.Close()
dstFile, err := os.OpenFile(dst, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, srcInfo.Mode())
if err != nil {
return err
}
defer dstFile.Close()
_, err = io.Copy(dstFile, srcFile)
if err != nil {
return err
}
// Preserve timestamps and ownership if possible
if stat, ok := srcInfo.Sys().(*syscall.Stat_t); ok {
wwlog.Debug("Updating ownership for file: %s", dst)
err = os.Chown(dst, int(stat.Uid), int(stat.Gid))
if err != nil {
wwlog.Warn("failed to update ownership for file %s: %s", dst, err)
}
}
err = os.Chtimes(dst, srcInfo.ModTime(), srcInfo.ModTime())
if err != nil {
wwlog.Warn("failed to update timestamps for file %s: %s", dst, err)
}
return nil
}
func cleanUp() {