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|
package namespace
import (
"fmt"
"os"
"path/filepath"
"strconv"
"syscall"
)
var runtimeBaseDir = func() string {
uid := os.Getuid()
base := fmt.Sprintf("/run/user/%d/wg-wrap", uid)
if envBase := os.Getenv("WG_WRAP_RUNTIME_DIR"); envBase != "" {
return envBase
}
return base
}()
// SetRuntimeBaseDir allows tests to override the base directory for namespace pins and PID tracking.
func SetRuntimeBaseDir(path string) {
runtimeBaseDir = path
}
// GetProfileNamespacePath returns the path to the pinned namespace file for a profile.
func GetProfileNamespacePath(profile string) string {
return filepath.Join(runtimeBaseDir, "profiles", profile)
}
// GetPidsDirPath returns the path to the directory where process PIDs are tracked for a profile.
func GetPidsDirPath(profile string) string {
return filepath.Join(GetProfileNamespacePath(profile), "pids")
}
// RegisterProcess marks the current process as using the specified profile.
func RegisterProcess(profile string) error {
pidsDir := GetPidsDirPath(profile)
if err := os.MkdirAll(pidsDir, 0755); err != nil {
return fmt.Errorf("failed to create pids directory: %v", err)
}
pid := os.Getpid()
pidFile := filepath.Join(pidsDir, strconv.Itoa(pid))
if err := os.WriteFile(pidFile, []byte(""), 0644); err != nil {
return fmt.Errorf("failed to register process pid %d: %v", pid, err)
}
return nil
}
// UnregisterProcess removes the current process from the profile's tracking.
func UnregisterProcess(profile string) error {
pid := os.Getpid()
pidFile := filepath.Join(GetPidsDirPath(profile), strconv.Itoa(pid))
if err := os.Remove(pidFile); err != nil && !os.IsNotExist(err) {
return fmt.Errorf("failed to unregister process pid %d: %v", pid, err)
}
return nil
}
// PruneStalePids removes PID files that no longer correspond to active processes.
func PruneStalePids(profile string) error {
pidsDir := GetPidsDirPath(profile)
files, err := os.ReadDir(pidsDir)
if err != nil {
if os.IsNotExist(err) {
return nil
}
return fmt.Errorf("failed to read pids directory: %v", err)
}
for _, file := range files {
pid, err := strconv.Atoi(file.Name())
if err != nil {
continue // Ignore non-numeric files
}
// Sending signal 0 checks if the process exists without actually killing it.
process, err := os.FindProcess(pid)
if err != nil {
os.Remove(filepath.Join(pidsDir, file.Name()))
continue
}
// On Unix, FindProcess always succeeds. We need to actually check if it's alive.
err = process.Signal(syscall.Signal(0))
if err != nil {
// Process is gone
os.Remove(filepath.Join(pidsDir, file.Name()))
}
}
return nil
}
// IsLastProcess checks if the current process is the only active user of the profile.
func IsLastProcess(profile string) (bool, error) {
pidsDir := GetPidsDirPath(profile)
files, err := os.ReadDir(pidsDir)
if err != nil {
if os.IsNotExist(err) {
return true, nil
}
return false, fmt.Errorf("failed to read pids directory: %w", err)
}
// We count how many PIDs are active, including ourselves.
activeCount := 0
for _, file := range files {
pid, err := strconv.Atoi(file.Name())
if err != nil {
continue
}
process, err := os.FindProcess(pid)
if err != nil {
continue
}
if process.Signal(syscall.Signal(0)) == nil {
activeCount++
}
}
return activeCount <= 1, nil
}
|
