blob: cd73f43043ee5aa63762c17c4549d1a3e38b9aa8 [file] [log] [blame]
// Copyright 2014 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package mobileinit
/*
To view the log output run:
adb logcat GoLog:I *:S
*/
// Android redirects stdout and stderr to /dev/null.
// As these are common debugging utilities in Go,
// we redirect them to logcat.
//
// Unfortunately, logcat is line oriented, so we must buffer.
/*
#cgo LDFLAGS: -landroid -llog
#include <android/log.h>
#include <stdlib.h>
#include <string.h>
*/
import "C"
import (
"bufio"
"log"
"os"
"syscall"
"unsafe"
)
var (
ctag = C.CString("GoLog")
// Store the writer end of the redirected stderr and stdout
// so that they are not garbage collected and closed.
stderr, stdout *os.File
)
type infoWriter struct{}
func (infoWriter) Write(p []byte) (n int, err error) {
cstr := C.CString(string(p))
C.__android_log_write(C.ANDROID_LOG_INFO, ctag, cstr)
C.free(unsafe.Pointer(cstr))
return len(p), nil
}
func lineLog(f *os.File, priority C.int) {
const logSize = 1024 // matches android/log.h.
r := bufio.NewReaderSize(f, logSize)
for {
line, _, err := r.ReadLine()
str := string(line)
if err != nil {
str += " " + err.Error()
}
cstr := C.CString(str)
C.__android_log_write(priority, ctag, cstr)
C.free(unsafe.Pointer(cstr))
if err != nil {
break
}
}
}
func init() {
log.SetOutput(infoWriter{})
// android logcat includes all of log.LstdFlags
log.SetFlags(log.Flags() &^ log.LstdFlags)
r, w, err := os.Pipe()
if err != nil {
panic(err)
}
stderr = w
if err := syscall.Dup3(int(w.Fd()), int(os.Stderr.Fd()), 0); err != nil {
panic(err)
}
go lineLog(r, C.ANDROID_LOG_ERROR)
r, w, err = os.Pipe()
if err != nil {
panic(err)
}
stdout = w
if err := syscall.Dup3(int(w.Fd()), int(os.Stdout.Fd()), 0); err != nil {
panic(err)
}
go lineLog(r, C.ANDROID_LOG_INFO)
}