You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
105 lines
3.8 KiB
105 lines
3.8 KiB
// Copyright (C) 2020 The Android Open Source Project
|
|
//
|
|
// Licensed under the Apache License, Version 2.0 (the "License");
|
|
// you may not use this file except in compliance with the License.
|
|
// You may obtain a copy of the License at
|
|
//
|
|
// http://www.apache.org/licenses/LICENSE-2.0
|
|
//
|
|
// Unless required by applicable law or agreed to in writing, software
|
|
// distributed under the License is distributed on an "AS IS" BASIS,
|
|
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
// See the License for the specific language governing permissions and
|
|
// limitations under the License.
|
|
|
|
#define LOG_TAG "netjniutils"
|
|
|
|
#include "netjniutils/netjniutils.h"
|
|
|
|
#include <dlfcn.h>
|
|
#include <stdbool.h>
|
|
#include <string.h>
|
|
#include <sys/system_properties.h>
|
|
|
|
#include <android/api-level.h>
|
|
#include <android/log.h>
|
|
|
|
namespace android {
|
|
namespace netjniutils {
|
|
|
|
namespace {
|
|
|
|
bool IsAtLeastS() {
|
|
// TODO(b/158749603#comment19): move to android::modules::sdklevel::IsAtLeastS().
|
|
int api_level = android_get_device_api_level();
|
|
|
|
// Guarded check for branches that do not have __ANDROID_API_S__.
|
|
#ifdef __ANDROID_API_S__
|
|
if (api_level >= __ANDROID_API_S__) {
|
|
return true;
|
|
}
|
|
#endif
|
|
|
|
if (api_level < __ANDROID_API_R__) {
|
|
return false;
|
|
}
|
|
|
|
// Device looks like R or above, check codename as it could be (S or above).
|
|
static constexpr const char* kCodenameProperty = "ro.build.version.codename";
|
|
char codename[PROP_VALUE_MAX] = { 0 };
|
|
return (__system_property_get(kCodenameProperty, codename) > 0 &&
|
|
codename[0] >= 'S' && codename[1] == '\0');
|
|
}
|
|
|
|
int GetNativeFileDescriptorWithoutNdk(JNIEnv* env, jobject javaFd) {
|
|
// Prior to Android S, we need to find the descriptor field in the FileDescriptor class. The
|
|
// symbol name has been stable in libcore, but is a private implementation detail.
|
|
// Older libnativehelper_compat_c++ versions had a jniGetFdFromFileDescriptor method, but this
|
|
// was removed in S to replace it with the NDK API in libnativehelper.
|
|
// The code is copied here instead. This code can be removed once R is not supported anymore.
|
|
static const jfieldID descriptorFieldID = [env]() -> jfieldID {
|
|
jclass cls = env->FindClass("java/io/FileDescriptor");
|
|
jfieldID fieldID = env->GetFieldID(cls, "descriptor", "I");
|
|
env->DeleteLocalRef(cls);
|
|
if (fieldID == nullptr) {
|
|
__android_log_print(ANDROID_LOG_FATAL, LOG_TAG, "Failed to get descriptor field.");
|
|
}
|
|
return fieldID;
|
|
}();
|
|
|
|
return javaFd != nullptr ? env->GetIntField(javaFd, descriptorFieldID) : -1;
|
|
}
|
|
|
|
int GetNativeFileDescriptorWithNdk(JNIEnv* env, jobject javaFd) {
|
|
// Since Android S, there is an NDK API to get a file descriptor present in libnativehelper.so.
|
|
// libnativehelper is loaded into all processes by the zygote since the zygote uses it
|
|
// to load the Android Runtime and is also a public library (because of the NDK API).
|
|
typedef int (*ndkGetFd_t)(JNIEnv*, jobject);
|
|
static const ndkGetFd_t ndkGetFd = []() -> ndkGetFd_t {
|
|
void* handle = dlopen("libnativehelper.so", RTLD_NOLOAD | RTLD_NODELETE);
|
|
auto ndkGetFd = reinterpret_cast<ndkGetFd_t>(dlsym(handle, "AFileDescriptor_getFd"));
|
|
if (ndkGetFd == nullptr) {
|
|
__android_log_print(ANDROID_LOG_FATAL, LOG_TAG,
|
|
"Failed to dlsym(AFileDescriptor_getFd): %s", dlerror());
|
|
dlclose(handle);
|
|
}
|
|
return ndkGetFd;
|
|
}();
|
|
|
|
return javaFd != nullptr ? ndkGetFd(env, javaFd) : -1;
|
|
}
|
|
|
|
} // namespace
|
|
|
|
int GetNativeFileDescriptor(JNIEnv* env, jobject javaFd) {
|
|
static const bool preferNdkFileDescriptorApi = []() -> bool { return IsAtLeastS(); }();
|
|
if (preferNdkFileDescriptorApi) {
|
|
return GetNativeFileDescriptorWithNdk(env, javaFd);
|
|
} else {
|
|
return GetNativeFileDescriptorWithoutNdk(env, javaFd);
|
|
}
|
|
}
|
|
|
|
} // namespace netjniutils
|
|
} // namespace android
|