sing-box/experimental/libbox/log.go

//go:build darwin || linux

package libbox

import (
	"os"

	"golang.org/x/sys/unix"
)

var stderrFile *os.File

func RedirectStderr(path string) error {
	if stats, err := os.Stat(path); err == nil && stats.Size() > 0 {
		_ = os.Rename(path, path+".old")
	}
	outputFile, err := os.Create(path)
	if err != nil {
		return err
	}
	if sUserID > 0 {
		err = outputFile.Chown(sUserID, sGroupID)
		if err != nil {
			outputFile.Close()
			os.Remove(outputFile.Name())
			return err
		}
	}
	err = unix.Dup2(int(outputFile.Fd()), int(os.Stderr.Fd()))
	if err != nil {
		outputFile.Close()
		os.Remove(outputFile.Name())
		return err
	}
	stderrFile = outputFile
	return nil
}