platform_system_core/libvndksupport/linker.cpp
Peter Collingbourne 683192270f Stop using weak symbols in libvndksupport.
These weak symbols are no longer necessary because we no longer
need to statically link libvndksupport.

Furthermore, these symbols are not really optional when libvndksupport is
dynamically linked. When the library is linked with --as-needed the linker
may drop the reference to libdl_android.so, which leads to a failure to boot.

Bug: 146456667
Change-Id: I4d2290d8d0206e0d89665d4d872a7c53b3e1531b
2019-12-17 17:52:05 -08:00

85 lines
2.5 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>
extern "C" android_namespace_t* android_get_exported_namespace(const char*);
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_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;
}
// 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 = 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);
}