add libvndksupport
libvndksupport is a new LL-NDK library that provides vendor-visible APIs
for platform-only functionalities of other LL-NDK libraries. Currently,
it provides android_(load|unload)_sphal_library which abstracts the
platform-only APIs of libdl (android_get_exported_namespace, etc.)
Bug: 37323945
Test: sailfish builds and boots
Test: libvndksupport-tests passes
Merged-In: I6d2911b57e009d0c842554933aac87d6573ffcbf
Change-Id: I6d2911b57e009d0c842554933aac87d6573ffcbf
(cherry picked from commit 7130e13262f788d35e85e0b38db58a1e2aa6266b)
diff --git a/libvndksupport/linker.c b/libvndksupport/linker.c
new file mode 100644
index 0000000..12aa3be
--- /dev/null
+++ b/libvndksupport/linker.c
@@ -0,0 +1,50 @@
+/*
+ * 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.
+ */
+#include "linker.h"
+
+#include <android/dlext.h>
+#include <dlfcn.h>
+
+#define LOG_TAG "vndksupport"
+#include <log/log.h>
+
+extern struct android_namespace_t* android_get_exported_namespace(const char*);
+
+void* android_load_sphal_library(const char* name, int flag) {
+ struct android_namespace_t* sphal_namespace = android_get_exported_namespace("sphal");
+ if (sphal_namespace != NULL) {
+ const android_dlextinfo dlextinfo = {
+ .flags = ANDROID_DLEXT_USE_NAMESPACE, .library_namespace = sphal_namespace,
+ };
+ void* handle = android_dlopen_ext(name, flag, &dlextinfo);
+ if (handle) {
+ return handle;
+ } else {
+ ALOGW(
+ "Could not load %s from sphal namespace: %s. "
+ "Falling back to loading it from the current namespace,",
+ name, dlerror());
+ }
+ } else {
+ ALOGI(
+ "sphal namespace is not configured for this process. "
+ "Loading %s from the current namespace instead.",
+ name);
+ }
+ return dlopen(name, flag);
+}
+
+int android_unload_sphal_library(void* handle) { return dlclose(handle); }