platform_system_core/libvndksupport/linker.cpp
Ryan Prichard 8c733615aa Make android_load_sphal_library thread-safe
Also: remove an obsolete comment from linker_test.cpp. The test program is
at /data/nativetest[64]/libvndksupport-tests/libvndksupport-tests, which
may will be in the system or legacy configuration, and either the "sphal"
or "default" namespace will be visible.

Bug: none
Test: run libvndksupport-tests, device boots
Change-Id: I5e33e5bf1402a0368e046b03827c216789b02c96
2019-07-15 13:58:51 -07:00

96 lines
3.1 KiB
C++

/*
* Copyright (C) 2017 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 "vndksupport"
#include "linker.h"
#include <android/dlext.h>
#include <dlfcn.h>
#include <log/log.h>
#include <sys/types.h>
#include <unistd.h>
#include <initializer_list>
__attribute__((weak)) extern "C" android_namespace_t* android_get_exported_namespace(const char*);
__attribute__((weak)) extern "C" void* android_dlopen_ext(const char*, int,
const android_dlextinfo*);
namespace {
struct VendorNamespace {
android_namespace_t* ptr = nullptr;
const char* name = nullptr;
};
} // anonymous namespace
static VendorNamespace get_vendor_namespace() {
static VendorNamespace result = ([] {
for (const char* name : {"sphal", "default"}) {
if (android_get_exported_namespace != nullptr) {
if (android_namespace_t* ns = android_get_exported_namespace(name)) {
return VendorNamespace{ns, name};
}
}
}
return VendorNamespace{};
})();
return result;
}
int android_is_in_vendor_process() {
// Special case init, since when init runs, ld.config.<ver>.txt hasn't been
// loaded (sysprop service isn't up for init to know <ver>).
if (getpid() == 1) {
return 0;
}
if (android_get_exported_namespace == nullptr) {
ALOGD("android_get_exported_namespace() not available. Assuming system process.");
return 0;
}
// In vendor process, 'vndk' namespace is not visible, whereas in system
// process, it is.
return android_get_exported_namespace("vndk") == nullptr;
}
void* android_load_sphal_library(const char* name, int flag) {
VendorNamespace vendor_namespace = get_vendor_namespace();
if (vendor_namespace.ptr != nullptr) {
const android_dlextinfo dlextinfo = {
.flags = ANDROID_DLEXT_USE_NAMESPACE,
.library_namespace = vendor_namespace.ptr,
};
void* handle = nullptr;
if (android_dlopen_ext != nullptr) {
handle = android_dlopen_ext(name, flag, &dlextinfo);
}
if (!handle) {
ALOGE("Could not load %s from %s namespace: %s.", name, vendor_namespace.name,
dlerror());
}
return handle;
} else {
ALOGD("Loading %s from current namespace instead of sphal namespace.", name);
return dlopen(name, flag);
}
}
int android_unload_sphal_library(void* handle) {
return dlclose(handle);
}