Add log redirection for Android

logger_android.go

@@ -0,0 +1,70 @@
+package libXray
+
+import (
+	"bufio"
+	"io"
+	"log"
+	"os"
+	"syscall"
+
+	"github.com/amnezia-vpn/amnezia-libxray/nodep"
+)
+
+type Logger interface {
+	io.Writer
+	Warning(s string)
+	Error(s string)
+}
+
+var (
+	// Store the writer end of the redirected stderr and stdout
+	// so that they are not garbage collected and closed.
+	stderr, stdout *os.File
+)
+
+func writeLog(stream *os.File, log func(s string), logError func(s string)) {
+	const logSize = 1024
+	r := bufio.NewReaderSize(stream, logSize)
+	for {
+		line, _, err := r.ReadLine()
+		str := string(line)
+		if err != nil {
+			str += " " + err.Error()
+			logError(str)
+			break
+		} else {
+			log(str)
+		}
+	}
+}
+
+func logStream(stream uintptr, log func(s string), logError func(s string)) (*os.File, error) {
+	r, w, err := os.Pipe()
+	if err != nil {
+		return nil, err
+	}
+	if err := syscall.Dup3(int(w.Fd()), int(stream), 0); err != nil {
+		return nil, err
+	}
+	go writeLog(r, log, logError)
+	return w, err
+}
+
+func InitLogger(logger Logger) string {
+	log.SetOutput(logger)
+	log.SetFlags(0)
+
+	stream, err := logStream(os.Stderr.Fd(), logger.Error, logger.Error)
+	if err != nil {
+		return nodep.WrapError(err)
+	}
+	stderr = stream
+
+	stream, err = logStream(os.Stdout.Fd(), logger.Warning, logger.Error)
+	if err != nil {
+		return nodep.WrapError(err)
+	}
+	stdout = stream
+
+	return ""
+}