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tailscale-android/cmd/jni/jni.go

490 lines
15 KiB
Go

// Copyright (c) 2020 Tailscale Inc & 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 jni implements various helper functions for communicating with the Android JVM
// though JNI.
package jni
import (
"errors"
"fmt"
"reflect"
"runtime"
"sync"
"unicode/utf16"
"unsafe"
)
/*
#cgo CFLAGS: -Wall
#include <jni.h>
#include <stdlib.h>
static jint jni_AttachCurrentThread(JavaVM *vm, JNIEnv **p_env, void *thr_args) {
return (*vm)->AttachCurrentThread(vm, p_env, thr_args);
}
static jint jni_DetachCurrentThread(JavaVM *vm) {
return (*vm)->DetachCurrentThread(vm);
}
static jint jni_GetEnv(JavaVM *vm, JNIEnv **env, jint version) {
return (*vm)->GetEnv(vm, (void **)env, version);
}
static jclass jni_FindClass(JNIEnv *env, const char *name) {
return (*env)->FindClass(env, name);
}
static jthrowable jni_ExceptionOccurred(JNIEnv *env) {
return (*env)->ExceptionOccurred(env);
}
static void jni_ExceptionClear(JNIEnv *env) {
(*env)->ExceptionClear(env);
}
static jclass jni_GetObjectClass(JNIEnv *env, jobject obj) {
return (*env)->GetObjectClass(env, obj);
}
static jmethodID jni_GetMethodID(JNIEnv *env, jclass clazz, const char *name, const char *sig) {
return (*env)->GetMethodID(env, clazz, name, sig);
}
static jmethodID jni_GetStaticMethodID(JNIEnv *env, jclass clazz, const char *name, const char *sig) {
return (*env)->GetStaticMethodID(env, clazz, name, sig);
}
static jsize jni_GetStringLength(JNIEnv *env, jstring str) {
return (*env)->GetStringLength(env, str);
}
static const jchar *jni_GetStringChars(JNIEnv *env, jstring str) {
return (*env)->GetStringChars(env, str, NULL);
}
static jstring jni_NewString(JNIEnv *env, const jchar *unicodeChars, jsize len) {
return (*env)->NewString(env, unicodeChars, len);
}
static jboolean jni_IsSameObject(JNIEnv *env, jobject ref1, jobject ref2) {
return (*env)->IsSameObject(env, ref1, ref2);
}
static jobject jni_NewGlobalRef(JNIEnv *env, jobject obj) {
return (*env)->NewGlobalRef(env, obj);
}
static void jni_DeleteGlobalRef(JNIEnv *env, jobject obj) {
(*env)->DeleteGlobalRef(env, obj);
}
static void jni_CallStaticVoidMethodA(JNIEnv *env, jclass cls, jmethodID method, jvalue *args) {
(*env)->CallStaticVoidMethodA(env, cls, method, args);
}
static jint jni_CallStaticIntMethodA(JNIEnv *env, jclass cls, jmethodID method, jvalue *args) {
return (*env)->CallStaticIntMethodA(env, cls, method, args);
}
static jobject jni_CallStaticObjectMethodA(JNIEnv *env, jclass cls, jmethodID method, jvalue *args) {
return (*env)->CallStaticObjectMethodA(env, cls, method, args);
}
static jobject jni_CallObjectMethodA(JNIEnv *env, jobject obj, jmethodID method, jvalue *args) {
return (*env)->CallObjectMethodA(env, obj, method, args);
}
static jboolean jni_CallBooleanMethodA(JNIEnv *env, jobject obj, jmethodID method, jvalue *args) {
return (*env)->CallBooleanMethodA(env, obj, method, args);
}
static jint jni_CallIntMethodA(JNIEnv *env, jobject obj, jmethodID method, jvalue *args) {
return (*env)->CallIntMethodA(env, obj, method, args);
}
static void jni_CallVoidMethodA(JNIEnv *env, jobject obj, jmethodID method, jvalue *args) {
(*env)->CallVoidMethodA(env, obj, method, args);
}
static jbyteArray jni_NewByteArray(JNIEnv *env, jsize length) {
return (*env)->NewByteArray(env, length);
}
static jboolean *jni_GetBooleanArrayElements(JNIEnv *env, jbooleanArray arr) {
return (*env)->GetBooleanArrayElements(env, arr, NULL);
}
static void jni_ReleaseBooleanArrayElements(JNIEnv *env, jbooleanArray arr, jboolean *elems, jint mode) {
(*env)->ReleaseBooleanArrayElements(env, arr, elems, mode);
}
static jbyte *jni_GetByteArrayElements(JNIEnv *env, jbyteArray arr) {
return (*env)->GetByteArrayElements(env, arr, NULL);
}
static jint *jni_GetIntArrayElements(JNIEnv *env, jintArray arr) {
return (*env)->GetIntArrayElements(env, arr, NULL);
}
static void jni_ReleaseIntArrayElements(JNIEnv *env, jintArray arr, jint *elems, jint mode) {
(*env)->ReleaseIntArrayElements(env, arr, elems, mode);
}
static jlong *jni_GetLongArrayElements(JNIEnv *env, jlongArray arr) {
return (*env)->GetLongArrayElements(env, arr, NULL);
}
static void jni_ReleaseLongArrayElements(JNIEnv *env, jlongArray arr, jlong *elems, jint mode) {
(*env)->ReleaseLongArrayElements(env, arr, elems, mode);
}
static void jni_ReleaseByteArrayElements(JNIEnv *env, jbyteArray arr, jbyte *elems, jint mode) {
(*env)->ReleaseByteArrayElements(env, arr, elems, mode);
}
static jsize jni_GetArrayLength(JNIEnv *env, jarray arr) {
return (*env)->GetArrayLength(env, arr);
}
static void jni_DeleteLocalRef(JNIEnv *env, jobject localRef) {
return (*env)->DeleteLocalRef(env, localRef);
}
static jobject jni_GetObjectArrayElement(JNIEnv *env, jobjectArray array, jsize index) {
return (*env)->GetObjectArrayElement(env, array, index);
}
static jboolean jni_IsInstanceOf(JNIEnv *env, jobject obj, jclass clazz) {
return (*env)->IsInstanceOf(env, obj, clazz);
}
*/
import "C"
type JVM C.JavaVM
type Env C.JNIEnv
type (
Class C.jclass
Object C.jobject
MethodID C.jmethodID
String C.jstring
ByteArray C.jbyteArray
ObjectArray C.jobjectArray
BooleanArray C.jbooleanArray
LongArray C.jlongArray
IntArray C.jintArray
Boolean C.jboolean
Value uint64 // All JNI types fit into 64-bits.
)
// Cached class handles.
var classes struct {
once sync.Once
stringClass, integerClass Class
integerIntValue MethodID
}
func env(e *Env) *C.JNIEnv {
return (*C.JNIEnv)(unsafe.Pointer(e))
}
func javavm(vm *JVM) *C.JavaVM {
return (*C.JavaVM)(unsafe.Pointer(vm))
}
// Do invokes a function with a temporary JVM environment. The
// environment is not valid after the function returns.
func Do(vm *JVM, f func(env *Env) error) error {
runtime.LockOSThread()
defer runtime.UnlockOSThread()
var env *C.JNIEnv
if res := C.jni_GetEnv(javavm(vm), &env, C.JNI_VERSION_1_6); res != C.JNI_OK {
if res != C.JNI_EDETACHED {
panic(fmt.Errorf("JNI GetEnv failed with error %d", res))
}
if C.jni_AttachCurrentThread(javavm(vm), &env, nil) != C.JNI_OK {
panic(errors.New("runInJVM: AttachCurrentThread failed"))
}
defer C.jni_DetachCurrentThread(javavm(vm))
}
return f((*Env)(unsafe.Pointer(env)))
}
func Bool(b bool) Boolean {
if b {
return C.JNI_TRUE
}
return C.JNI_FALSE
}
func varArgs(args []Value) *C.jvalue {
if len(args) == 0 {
return nil
}
return (*C.jvalue)(unsafe.Pointer(&args[0]))
}
func IsSameObject(e *Env, ref1, ref2 Object) bool {
same := C.jni_IsSameObject(env(e), C.jobject(ref1), C.jobject(ref2))
return same == C.JNI_TRUE
}
func CallStaticIntMethod(e *Env, cls Class, method MethodID, args ...Value) (int, error) {
res := C.jni_CallStaticIntMethodA(env(e), C.jclass(cls), C.jmethodID(method), varArgs(args))
return int(res), exception(e)
}
func CallStaticVoidMethod(e *Env, cls Class, method MethodID, args ...Value) error {
C.jni_CallStaticVoidMethodA(env(e), C.jclass(cls), C.jmethodID(method), varArgs(args))
return exception(e)
}
func CallVoidMethod(e *Env, obj Object, method MethodID, args ...Value) error {
C.jni_CallVoidMethodA(env(e), C.jobject(obj), C.jmethodID(method), varArgs(args))
return exception(e)
}
func CallStaticObjectMethod(e *Env, cls Class, method MethodID, args ...Value) (Object, error) {
res := C.jni_CallStaticObjectMethodA(env(e), C.jclass(cls), C.jmethodID(method), varArgs(args))
return Object(res), exception(e)
}
func CallObjectMethod(e *Env, obj Object, method MethodID, args ...Value) (Object, error) {
res := C.jni_CallObjectMethodA(env(e), C.jobject(obj), C.jmethodID(method), varArgs(args))
return Object(res), exception(e)
}
func CallBooleanMethod(e *Env, obj Object, method MethodID, args ...Value) (bool, error) {
res := C.jni_CallBooleanMethodA(env(e), C.jobject(obj), C.jmethodID(method), varArgs(args))
return res == C.JNI_TRUE, exception(e)
}
func CallIntMethod(e *Env, obj Object, method MethodID, args ...Value) (int32, error) {
res := C.jni_CallIntMethodA(env(e), C.jobject(obj), C.jmethodID(method), varArgs(args))
return int32(res), exception(e)
}
// GetByteArrayElements returns the contents of the byte array.
func GetByteArrayElements(e *Env, jarr ByteArray) []byte {
if jarr == 0 {
return nil
}
size := C.jni_GetArrayLength(env(e), C.jarray(jarr))
elems := C.jni_GetByteArrayElements(env(e), C.jbyteArray(jarr))
defer C.jni_ReleaseByteArrayElements(env(e), C.jbyteArray(jarr), elems, 0)
backing := (*(*[1 << 30]byte)(unsafe.Pointer(elems)))[:size:size]
s := make([]byte, len(backing))
copy(s, backing)
return s
}
// GetBooleanArrayElements returns the contents of the boolean array.
func GetBooleanArrayElements(e *Env, jarr BooleanArray) []bool {
if jarr == 0 {
return nil
}
size := C.jni_GetArrayLength(env(e), C.jarray(jarr))
elems := C.jni_GetBooleanArrayElements(env(e), C.jbooleanArray(jarr))
defer C.jni_ReleaseBooleanArrayElements(env(e), C.jbooleanArray(jarr), elems, 0)
backing := (*(*[1 << 30]C.jboolean)(unsafe.Pointer(elems)))[:size:size]
r := make([]bool, len(backing))
for i, b := range backing {
r[i] = b == C.JNI_TRUE
}
return r
}
// GetStringArrayElements returns the contents of the String array.
func GetStringArrayElements(e *Env, jarr ObjectArray) []string {
var strings []string
iterateObjectArray(e, jarr, func(e *Env, idx int, item Object) {
s := GoString(e, String(item))
strings = append(strings, s)
})
return strings
}
// GetIntArrayElements returns the contents of the int array.
func GetIntArrayElements(e *Env, jarr IntArray) []int {
if jarr == 0 {
return nil
}
size := C.jni_GetArrayLength(env(e), C.jarray(jarr))
elems := C.jni_GetIntArrayElements(env(e), C.jintArray(jarr))
defer C.jni_ReleaseIntArrayElements(env(e), C.jintArray(jarr), elems, 0)
backing := (*(*[1 << 27]C.jint)(unsafe.Pointer(elems)))[:size:size]
r := make([]int, len(backing))
for i, l := range backing {
r[i] = int(l)
}
return r
}
// GetLongArrayElements returns the contents of the long array.
func GetLongArrayElements(e *Env, jarr LongArray) []int64 {
if jarr == 0 {
return nil
}
size := C.jni_GetArrayLength(env(e), C.jarray(jarr))
elems := C.jni_GetLongArrayElements(env(e), C.jlongArray(jarr))
defer C.jni_ReleaseLongArrayElements(env(e), C.jlongArray(jarr), elems, 0)
backing := (*(*[1 << 27]C.jlong)(unsafe.Pointer(elems)))[:size:size]
r := make([]int64, len(backing))
for i, l := range backing {
r[i] = int64(l)
}
return r
}
func iterateObjectArray(e *Env, jarr ObjectArray, f func(e *Env, idx int, item Object)) {
if jarr == 0 {
return
}
size := C.jni_GetArrayLength(env(e), C.jarray(jarr))
for i := 0; i < int(size); i++ {
item := C.jni_GetObjectArrayElement(env(e), C.jobjectArray(jarr), C.jint(i))
f(e, i, Object(item))
C.jni_DeleteLocalRef(env(e), item)
}
}
// NewByteArray allocates a Java byte array with the content. It
// panics if the allocation fails.
func NewByteArray(e *Env, content []byte) ByteArray {
jarr := C.jni_NewByteArray(env(e), C.jsize(len(content)))
if jarr == 0 {
panic(fmt.Errorf("jni: NewByteArray(%d) failed", len(content)))
}
elems := C.jni_GetByteArrayElements(env(e), jarr)
defer C.jni_ReleaseByteArrayElements(env(e), jarr, elems, 0)
backing := (*(*[1 << 30]byte)(unsafe.Pointer(elems)))[:len(content):len(content)]
copy(backing, content)
return ByteArray(jarr)
}
// ClassLoader returns a reference to the Java ClassLoader associated
// with obj.
func ClassLoaderFor(e *Env, obj Object) Object {
cls := GetObjectClass(e, obj)
getClassLoader := GetMethodID(e, cls, "getClassLoader", "()Ljava/lang/ClassLoader;")
clsLoader, err := CallObjectMethod(e, Object(obj), getClassLoader)
if err != nil {
// Class.getClassLoader should never fail.
panic(err)
}
return Object(clsLoader)
}
// LoadClass invokes the underlying ClassLoader's loadClass method and
// returns the class.
func LoadClass(e *Env, loader Object, class string) (Class, error) {
cls := GetObjectClass(e, loader)
loadClass := GetMethodID(e, cls, "loadClass", "(Ljava/lang/String;)Ljava/lang/Class;")
name := JavaString(e, class)
loaded, err := CallObjectMethod(e, loader, loadClass, Value(name))
if err != nil {
return 0, err
}
return Class(loaded), exception(e)
}
// exception returns an error corresponding to the pending
// exception, and clears it. exceptionError returns nil if no
// exception is pending.
func exception(e *Env) error {
thr := C.jni_ExceptionOccurred(env(e))
if thr == 0 {
return nil
}
C.jni_ExceptionClear(env(e))
cls := GetObjectClass(e, Object(thr))
toString := GetMethodID(e, cls, "toString", "()Ljava/lang/String;")
msg, err := CallObjectMethod(e, Object(thr), toString)
if err != nil {
return err
}
return errors.New(GoString(e, String(msg)))
}
// GetObjectClass returns the Java Class for an Object.
func GetObjectClass(e *Env, obj Object) Class {
if obj == 0 {
panic("null object")
}
cls := C.jni_GetObjectClass(env(e), C.jobject(obj))
if err := exception(e); err != nil {
// GetObjectClass should never fail.
panic(err)
}
return Class(cls)
}
// GetStaticMethodID returns the id for a static method. It panics if the method
// wasn't found.
func GetStaticMethodID(e *Env, cls Class, name, signature string) MethodID {
mname := C.CString(name)
defer C.free(unsafe.Pointer(mname))
msig := C.CString(signature)
defer C.free(unsafe.Pointer(msig))
m := C.jni_GetStaticMethodID(env(e), C.jclass(cls), mname, msig)
if err := exception(e); err != nil {
panic(err)
}
return MethodID(m)
}
// GetMethodID returns the id for a method. It panics if the method
// wasn't found.
func GetMethodID(e *Env, cls Class, name, signature string) MethodID {
mname := C.CString(name)
defer C.free(unsafe.Pointer(mname))
msig := C.CString(signature)
defer C.free(unsafe.Pointer(msig))
m := C.jni_GetMethodID(env(e), C.jclass(cls), mname, msig)
if err := exception(e); err != nil {
panic(err)
}
return MethodID(m)
}
func NewGlobalRef(e *Env, obj Object) Object {
return Object(C.jni_NewGlobalRef(env(e), C.jobject(obj)))
}
func DeleteGlobalRef(e *Env, obj Object) {
C.jni_DeleteGlobalRef(env(e), C.jobject(obj))
}
// JavaString converts the string to a JVM jstring.
func JavaString(e *Env, str string) String {
if str == "" {
return 0
}
utf16Chars := utf16.Encode([]rune(str))
res := C.jni_NewString(env(e), (*C.jchar)(unsafe.Pointer(&utf16Chars[0])), C.int(len(utf16Chars)))
return String(res)
}
// GoString converts the JVM jstring to a Go string.
func GoString(e *Env, str String) string {
if str == 0 {
return ""
}
strlen := C.jni_GetStringLength(env(e), C.jstring(str))
chars := C.jni_GetStringChars(env(e), C.jstring(str))
var utf16Chars []uint16
hdr := (*reflect.SliceHeader)(unsafe.Pointer(&utf16Chars))
hdr.Data = uintptr(unsafe.Pointer(chars))
hdr.Cap = int(strlen)
hdr.Len = int(strlen)
utf8 := utf16.Decode(utf16Chars)
return string(utf8)
}