Files

600 lines
15 KiB
Go

//go:build linux
// +build linux
package persistence
import (
"fmt"
"io"
"os"
"os/exec"
"os/user"
"path/filepath"
"strings"
"text/template"
)
var activateLinuxPersistence = true
var runLinuxCommand = func(name string, args ...string) ([]byte, error) {
return exec.Command(name, args...).CombinedOutput()
}
var runLinuxCommandInput = func(input []byte, name string, args ...string) ([]byte, error) {
cmd := exec.Command(name, args...)
stdin, err := cmd.StdinPipe()
if err != nil {
return nil, err
}
go func() {
defer stdin.Close()
_, _ = stdin.Write(input)
}()
return cmd.CombinedOutput()
}
var currentEUID = os.Geteuid
var currentUserHomeDir = func() (string, error) {
usr, err := user.Current()
if err != nil {
return "", err
}
if usr.HomeDir == "" {
return "", fmt.Errorf("current user home directory is empty")
}
return usr.HomeDir, nil
}
const systemdService = `[Unit]
Description=Overlord Agent
After=network.target
[Service]
Type=simple
ExecStart={{.ExePath}}
Restart=always
RestartSec=10
[Install]
WantedBy=default.target
`
const desktopEntry = `[Desktop Entry]
Type=Application
Name=Overlord Agent
Exec={{.ExePath}}
Hidden=false
NoDisplay=false
X-GNOME-Autostart-enabled=true
`
const openRCScript = `#!/sbin/openrc-run
description="Overlord Agent"
command={{.ExePath}}
command_background=true
pidfile="${XDG_RUNTIME_DIR:-/tmp}/{{.ServiceName}}.pid"
respawn_delay=10
respawn_max=0
`
func binaryName() string {
if DefaultStartupName != "" {
return DefaultStartupName
}
return "agent"
}
func getSystemdPath() (string, error) {
homeDir, err := currentUserHomeDir()
if err != nil {
return "", err
}
return filepath.Join(homeDir, ".config", "systemd", "user", binaryName()+".service"), nil
}
func getAutostartPath() (string, error) {
homeDir, err := currentUserHomeDir()
if err != nil {
return "", err
}
return filepath.Join(homeDir, ".config", "autostart", binaryName()+".desktop"), nil
}
func getOpenRCPath() (string, error) {
name := openRCServiceName()
if currentEUID() == 0 {
return filepath.Join(string(filepath.Separator), "etc", "init.d", name), nil
}
homeDir, err := currentUserHomeDir()
if err != nil {
return "", err
}
return filepath.Join(homeDir, ".config", "openrc", "init.d", name), nil
}
func getTargetPath() (string, error) {
homeDir, err := currentUserHomeDir()
if err != nil {
return "", err
}
return filepath.Join(homeDir, ".local", "share", "overlord", binaryName()), nil
}
func install(exePath string) error {
targetPath, err := getTargetPath()
if err != nil {
return fmt.Errorf("failed to get target path: %w", err)
}
dir := filepath.Dir(targetPath)
if err := os.MkdirAll(dir, 0755); err != nil {
return fmt.Errorf("failed to create overlord directory: %w", err)
}
if err := replaceExecutable(exePath, targetPath); err != nil {
return err
}
return installLinuxStartup(targetPath)
}
func replaceExecutable(exePath, targetPath string) error {
srcFile, err := os.Open(exePath)
if err != nil {
return fmt.Errorf("failed to open source executable: %w", err)
}
defer srcFile.Close()
dir := filepath.Dir(targetPath)
tmpFile, err := os.CreateTemp(dir, "agent-*.tmp")
if err != nil {
return fmt.Errorf("failed to create temp executable: %w", err)
}
tmpPath := tmpFile.Name()
defer func() {
_ = tmpFile.Close()
_ = os.Remove(tmpPath)
}()
if _, err := io.Copy(tmpFile, srcFile); err != nil {
return fmt.Errorf("failed to copy executable: %w", err)
}
if err := tmpFile.Sync(); err != nil {
return fmt.Errorf("failed to sync temp file: %w", err)
}
if err := tmpFile.Close(); err != nil {
return fmt.Errorf("failed to close temp file: %w", err)
}
if err := os.Rename(tmpPath, targetPath); err != nil {
if removeErr := os.Remove(targetPath); removeErr == nil {
err = os.Rename(tmpPath, targetPath)
}
if err != nil {
return fmt.Errorf("failed to replace executable at %s: %w", targetPath, err)
}
}
if err := os.Chmod(targetPath, 0755); err != nil {
return fmt.Errorf("failed to set executable permissions: %w", err)
}
return nil
}
func installSystemd(exePath string) error {
servicePath, err := getSystemdPath()
if err != nil {
return err
}
dir := filepath.Dir(servicePath)
if err := os.MkdirAll(dir, 0755); err != nil {
return fmt.Errorf("failed to create systemd directory: %w", err)
}
file, err := os.Create(servicePath)
if err != nil {
return fmt.Errorf("failed to create service file: %w", err)
}
tmpl, err := template.New("service").Parse(systemdService)
if err != nil {
_ = file.Close()
return fmt.Errorf("failed to parse template: %w", err)
}
data := struct {
ExePath string
}{
ExePath: exePath,
}
if err := tmpl.Execute(file, data); err != nil {
_ = file.Close()
return fmt.Errorf("failed to write service file: %w", err)
}
if err := file.Close(); err != nil {
return fmt.Errorf("failed to close service file: %w", err)
}
if activateLinuxPersistence {
if err := activateSystemdUser(servicePath); err != nil {
return fmt.Errorf("failed to activate systemd user service: %w", err)
}
}
return nil
}
func configure(exePath string) error {
return installLinuxStartup(exePath)
}
func installLinuxStartup(exePath string) error {
var firstErr error
for _, fn := range []func(string) error{
installSystemd,
installOpenRC,
installCronFallbackIfActive,
installAutostart,
} {
if err := fn(exePath); err == nil {
return nil
} else if firstErr == nil {
firstErr = err
}
}
return firstErr
}
func installAutostart(exePath string) error {
autostartPath, err := getAutostartPath()
if err != nil {
return err
}
dir := filepath.Dir(autostartPath)
if err := os.MkdirAll(dir, 0755); err != nil {
return fmt.Errorf("failed to create autostart directory: %w", err)
}
file, err := os.Create(autostartPath)
if err != nil {
return fmt.Errorf("failed to create desktop entry: %w", err)
}
defer file.Close()
tmpl, err := template.New("desktop").Parse(desktopEntry)
if err != nil {
return fmt.Errorf("failed to parse template: %w", err)
}
data := struct {
ExePath string
}{
ExePath: exePath,
}
if err := tmpl.Execute(file, data); err != nil {
return fmt.Errorf("failed to write desktop entry: %w", err)
}
return nil
}
func installOpenRC(exePath string) error {
servicePath, err := getOpenRCPath()
if err != nil {
return err
}
dir := filepath.Dir(servicePath)
if err := os.MkdirAll(dir, 0755); err != nil {
return fmt.Errorf("failed to create OpenRC directory: %w", err)
}
file, err := os.Create(servicePath)
if err != nil {
return fmt.Errorf("failed to create OpenRC service: %w", err)
}
tmpl, err := template.New("openrc").Parse(openRCScript)
if err != nil {
_ = file.Close()
return fmt.Errorf("failed to parse OpenRC template: %w", err)
}
data := struct {
ExePath string
ServiceName string
}{
ExePath: shellQuote(exePath),
ServiceName: openRCServiceName(),
}
if err := tmpl.Execute(file, data); err != nil {
_ = file.Close()
return fmt.Errorf("failed to write OpenRC service: %w", err)
}
if err := file.Close(); err != nil {
return fmt.Errorf("failed to close OpenRC service: %w", err)
}
if err := os.Chmod(servicePath, 0755); err != nil {
return fmt.Errorf("failed to set OpenRC service permissions: %w", err)
}
if activateLinuxPersistence {
if err := activateOpenRC(servicePath); err != nil {
return fmt.Errorf("failed to activate OpenRC service: %w", err)
}
}
return nil
}
func uninstall() error {
var lastErr error
if servicePath, err := getSystemdPath(); err == nil {
if err := os.Remove(servicePath); err != nil && !os.IsNotExist(err) {
lastErr = fmt.Errorf("failed to remove systemd service: %w", err)
}
}
if autostartPath, err := getAutostartPath(); err == nil {
if err := os.Remove(autostartPath); err != nil && !os.IsNotExist(err) {
lastErr = fmt.Errorf("failed to remove autostart entry: %w", err)
}
}
if err := removeOpenRC(); err != nil {
lastErr = err
}
if err := removeCronFallback(); err != nil {
lastErr = err
}
if targetPath, err := getTargetPath(); err == nil {
os.Remove(targetPath)
}
return lastErr
}
func activateSystemdUser(servicePath string) error {
serviceName := filepath.Base(servicePath)
if out, err := runLinuxCommand("systemctl", "--user", "daemon-reload"); err != nil {
return fmt.Errorf("systemctl --user daemon-reload: %w: %s", err, strings.TrimSpace(string(out)))
}
if out, err := runLinuxCommand("systemctl", "--user", "enable", servicePath); err != nil {
return fmt.Errorf("systemctl --user enable: %w: %s", err, strings.TrimSpace(string(out)))
}
if out, err := runLinuxCommand("systemctl", "--user", "restart", serviceName); err != nil {
return fmt.Errorf("systemctl --user restart: %w: %s", err, strings.TrimSpace(string(out)))
}
return nil
}
func activateOpenRC(servicePath string) error {
serviceName := filepath.Base(servicePath)
if currentEUID() == 0 {
if out, err := runLinuxCommand("rc-update", "add", serviceName, "default"); err != nil {
return fmt.Errorf("rc-update add: %w: %s", err, strings.TrimSpace(string(out)))
}
if out, err := runLinuxCommand("rc-service", serviceName, "restart"); err != nil {
return fmt.Errorf("rc-service restart: %w: %s", err, strings.TrimSpace(string(out)))
}
return nil
}
if out, err := runLinuxCommand("rc-update", "--user", "add", serviceName, "default"); err != nil {
return fmt.Errorf("rc-update --user add: %w: %s", err, strings.TrimSpace(string(out)))
}
if out, err := runLinuxCommand("rc-service", "--user", serviceName, "restart"); err != nil {
return fmt.Errorf("rc-service --user restart: %w: %s", err, strings.TrimSpace(string(out)))
}
return nil
}
func removeOpenRC() error {
servicePath, err := getOpenRCPath()
if err != nil {
return nil
}
if _, statErr := os.Stat(servicePath); statErr != nil {
if os.IsNotExist(statErr) {
return nil
}
return fmt.Errorf("failed to stat OpenRC service: %w", statErr)
}
serviceName := filepath.Base(servicePath)
if activateLinuxPersistence {
if currentEUID() == 0 {
_, _ = runLinuxCommand("rc-service", serviceName, "stop")
_, _ = runLinuxCommand("rc-update", "del", serviceName, "default")
} else {
_, _ = runLinuxCommand("rc-service", "--user", serviceName, "stop")
_, _ = runLinuxCommand("rc-update", "--user", "del", serviceName, "default")
}
}
if err := os.Remove(servicePath); err != nil && !os.IsNotExist(err) {
return fmt.Errorf("failed to remove OpenRC service: %w", err)
}
return nil
}
func installCronFallbackIfActive(exePath string) error {
if !activateLinuxPersistence {
return fmt.Errorf("cron fallback activation disabled")
}
return installCronFallback(exePath)
}
func cronMarker() string {
return "# overlord-agent:" + binaryName()
}
func cronCommand(exePath string) string {
quotedExe := shellQuote(exePath)
return fmt.Sprintf("* * * * * pgrep -u \"$USER\" -fx %s >/dev/null 2>&1 || %s >/dev/null 2>&1 &", quotedExe, quotedExe)
}
func installCronFallback(exePath string) error {
existing, err := currentCrontab()
if err != nil {
return err
}
next := withoutCronFallback(existing)
if strings.TrimSpace(next) != "" && !strings.HasSuffix(next, "\n") {
next += "\n"
}
next += cronMarker() + "\n" + cronCommand(exePath) + "\n"
if out, err := runLinuxCommandInput([]byte(next), "crontab", "-"); err != nil {
return fmt.Errorf("crontab install: %w: %s", err, strings.TrimSpace(string(out)))
}
return nil
}
func removeCronFallback() error {
existing, err := currentCrontab()
if err != nil {
return err
}
next := withoutCronFallback(existing)
if next == existing {
return nil
}
if out, err := runLinuxCommandInput([]byte(next), "crontab", "-"); err != nil {
return fmt.Errorf("failed to remove cron fallback: %w: %s", err, strings.TrimSpace(string(out)))
}
return nil
}
func currentCrontab() (string, error) {
out, err := runLinuxCommand("crontab", "-l")
if err != nil {
text := strings.ToLower(string(out))
if strings.Contains(text, "no crontab") || strings.Contains(text, "no crontab for") {
return "", nil
}
return "", fmt.Errorf("crontab -l: %w: %s", err, strings.TrimSpace(string(out)))
}
return string(out), nil
}
func withoutCronFallback(crontab string) string {
lines := strings.Split(crontab, "\n")
out := make([]string, 0, len(lines))
skipNext := false
removed := false
for _, line := range lines {
if skipNext {
skipNext = false
removed = true
continue
}
if strings.TrimSpace(line) == cronMarker() {
skipNext = true
removed = true
continue
}
out = append(out, line)
}
if !removed {
return crontab
}
return strings.TrimRight(strings.Join(out, "\n"), "\n")
}
func shellQuote(value string) string {
return "'" + strings.ReplaceAll(value, "'", "'\"'\"'") + "'"
}
func openRCServiceName() string {
raw := strings.TrimSpace(binaryName())
var builder strings.Builder
for _, r := range raw {
if (r >= 'a' && r <= 'z') || (r >= 'A' && r <= 'Z') || (r >= '0' && r <= '9') || r == '-' || r == '_' || r == '.' {
builder.WriteRune(r)
} else {
builder.WriteByte('_')
}
}
name := strings.Trim(builder.String(), "._-")
if name == "" {
return "agent"
}
return name
}
func removeCurrentInstall(currentExe string) error {
currentExe = filepath.Clean(strings.TrimSpace(currentExe))
if currentExe == "" || !currentProcessOwnsPath(currentExe) {
return nil
}
var lastErr error
if servicePath, err := getSystemdPath(); err == nil && startupFileReferences(servicePath, "ExecStart=", currentExe) {
if err := os.Remove(servicePath); err != nil && !os.IsNotExist(err) {
lastErr = fmt.Errorf("failed to remove current systemd service: %w", err)
}
}
if autostartPath, err := getAutostartPath(); err == nil && startupFileReferences(autostartPath, "Exec=", currentExe) {
if err := os.Remove(autostartPath); err != nil && !os.IsNotExist(err) {
lastErr = fmt.Errorf("failed to remove current autostart entry: %w", err)
}
}
if openRCPath, err := getOpenRCPath(); err == nil && startupFileContainsExecutable(openRCPath, currentExe) {
if err := os.Remove(openRCPath); err != nil && !os.IsNotExist(err) {
lastErr = fmt.Errorf("failed to remove current OpenRC service: %w", err)
}
}
if targetPath, err := getTargetPath(); err == nil && filepath.Clean(targetPath) == currentExe {
if err := os.Remove(targetPath); err != nil && !os.IsNotExist(err) {
lastErr = fmt.Errorf("failed to remove current executable: %w", err)
}
}
return lastErr
}
func startupFileReferences(path string, prefix string, exePath string) bool {
data, err := os.ReadFile(path)
if err != nil {
return false
}
for _, line := range strings.Split(string(data), "\n") {
if strings.TrimSpace(line) == prefix+exePath {
return true
}
}
return false
}
func startupFileContainsExecutable(path string, exePath string) bool {
data, err := os.ReadFile(path)
if err != nil {
return false
}
return strings.Contains(string(data), shellQuote(exePath)) || strings.Contains(string(data), exePath)
}
func currentProcessOwnsPath(path string) bool {
procInfo, err := os.Stat("/proc/self/exe")
if err != nil {
return false
}
pathInfo, err := os.Stat(path)
if err != nil {
return false
}
return os.SameFile(procInfo, pathInfo)
}