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/Android.bp b/libvndksupport/Android.bp
new file mode 100644
index 0000000..ab9e26f
--- /dev/null
+++ b/libvndksupport/Android.bp
@@ -0,0 +1,15 @@
+subdirs = ["tests"]
+
+cc_library_shared {
+ name: "libvndksupport",
+ srcs: ["linker.c"],
+ local_include_dirs: ["include/vndksupport"],
+ export_include_dirs: ["include"],
+ shared_libs: ["liblog"],
+}
+
+llndk_library {
+ name: "libvndksupport",
+ symbol_file: "libvndksupport.map.txt",
+ export_include_dirs: ["include"],
+}
diff --git a/libvndksupport/include/vndksupport/linker.h b/libvndksupport/include/vndksupport/linker.h
new file mode 100644
index 0000000..f509564
--- /dev/null
+++ b/libvndksupport/include/vndksupport/linker.h
@@ -0,0 +1,31 @@
+/*
+ * 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.
+ */
+#ifndef VNDKSUPPORT_LINKER_H_
+#define VNDKSUPPORT_LINKER_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+void* android_load_sphal_library(const char* name, int flag);
+
+int android_unload_sphal_library(void* handle);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // VNDKSUPPORT_LINKER_H_
diff --git a/libvndksupport/libvndksupport.map.txt b/libvndksupport/libvndksupport.map.txt
new file mode 100644
index 0000000..16e38da
--- /dev/null
+++ b/libvndksupport/libvndksupport.map.txt
@@ -0,0 +1,7 @@
+LIBVNDKSUPPORT {
+ global:
+ android_load_sphal_library; # vndk
+ android_unload_sphal_library; # vndk
+ local:
+ *;
+};
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); }
diff --git a/libvndksupport/tests/Android.bp b/libvndksupport/tests/Android.bp
new file mode 100644
index 0000000..3587cf8
--- /dev/null
+++ b/libvndksupport/tests/Android.bp
@@ -0,0 +1,26 @@
+// 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.
+
+cc_test {
+ name: "libvndksupport-tests",
+ srcs: [
+ "linker_test.cpp",
+ ],
+
+ host_supported: false,
+ shared_libs: [
+ "libvndksupport",
+ "libbase",
+ ]
+}
diff --git a/libvndksupport/tests/linker_test.cpp b/libvndksupport/tests/linker_test.cpp
new file mode 100644
index 0000000..7ce27d4
--- /dev/null
+++ b/libvndksupport/tests/linker_test.cpp
@@ -0,0 +1,60 @@
+/*
+ * 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 <gtest/gtest.h>
+
+#include <android-base/strings.h>
+#include <dirent.h>
+#include <dlfcn.h>
+#include <vndksupport/linker.h>
+#include <string>
+
+// Since the test executable will be in /data and ld.config.txt does not
+// configure sphal namespace for executables in /data, the call to
+// android_load_sphal_library will always fallback to the plain dlopen from the
+// default namespace.
+
+// Let's use libEGL_<chipset>.so as a SP-HAL in test
+static std::string find_sphal_lib() {
+ const char* path =
+#if defined(__LP64__)
+ "/vendor/lib64/egl";
+#else
+ "/vendor/lib/egl";
+#endif
+ std::unique_ptr<DIR, decltype(&closedir)> dir(opendir(path), closedir);
+
+ dirent* dp;
+ while ((dp = readdir(dir.get())) != nullptr) {
+ std::string name = dp->d_name;
+ if (android::base::StartsWith(name, "libEGL_")) {
+ return std::string(path) + "/" + name;
+ }
+ }
+ return "";
+}
+
+TEST(linker, load_existing_lib) {
+ std::string name = find_sphal_lib();
+ ASSERT_NE("", name);
+ void* handle = android_load_sphal_library(name.c_str(), RTLD_NOW | RTLD_LOCAL);
+ ASSERT_NE(nullptr, handle);
+ android_unload_sphal_library(handle);
+}
+
+TEST(linker, load_nonexisting_lib) {
+ void* handle = android_load_sphal_library("libNeverUseThisName.so", RTLD_NOW | RTLD_LOCAL);
+ ASSERT_EQ(nullptr, handle);
+}