Move linker-namespace functions declarations

They are intended for platform use only and we shouldn't have them
in the public header file. This CL moves them to libnativeloader
private header file.

Bug: http://b/28174921
Change-Id: I01cf446d2d8d7cf6f9e31130aa3d4e54fbbbb9fc

2 files changed, 91 insertions, 1 deletions

diff --git a/libnativeloader/dlext_namespaces.h b/libnativeloader/dlext_namespaces.h
new file mode 100644
index 000000000..ca9e61979
--- /dev/null
+++ b/libnativeloader/dlext_namespaces.h
@@ -0,0 +1,90 @@
+/*
+ * Copyright (C) 2016 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 __ANDROID_DLEXT_NAMESPACES_H__
+#define __ANDROID_DLEXT_NAMESPACES_H__
+
+#include <android/dlext.h>
+
+__BEGIN_DECLS
+
+/*
+ * Initializes public and anonymous namespaces. The public_ns_sonames is the list of sonames
+ * to be included into public namespace separated by colon. Example: "libc.so:libm.so:libdl.so".
+ * The libraries in this list should be loaded prior to this call.
+ *
+ * The anon_ns_library_path is the search path for anonymous namespace. The anonymous namespace
+ * is used in the case when linker cannot identify the caller of dlopen/dlsym. This happens
+ * for the code not loaded by dynamic linker; for example calls from the mono-compiled code.
+ */
+extern bool android_init_namespaces(const char* public_ns_sonames,
+                                    const char* anon_ns_library_path);
+
+
+enum {
+  /* A regular namespace is the namespace with a custom search path that does
+   * not impose any restrictions on the location of native libraries.
+   */
+  ANDROID_NAMESPACE_TYPE_REGULAR = 0,
+
+  /* An isolated namespace requires all the libraries to be on the search path
+   * or under permitted_when_isolated_path. The search path is the union of
+   * ld_library_path and default_library_path.
+   */
+  ANDROID_NAMESPACE_TYPE_ISOLATED = 1,
+
+  /* The shared namespace clones the list of libraries of the caller namespace upon creation
+   * which means that they are shared between namespaces - the caller namespace and the new one
+   * will use the same copy of a library if it was loaded prior to android_create_namespace call.
+   *
+   * Note that libraries loaded after the namespace is created will not be shared.
+   *
+   * Shared namespaces can be isolated or regular. Note that they do not inherit the search path nor
+   * permitted_path from the caller's namespace.
+   */
+  ANDROID_NAMESPACE_TYPE_SHARED = 2,
+  ANDROID_NAMESPACE_TYPE_SHARED_ISOLATED = ANDROID_NAMESPACE_TYPE_SHARED |
+                                           ANDROID_NAMESPACE_TYPE_ISOLATED,
+};
+
+/*
+ * Creates new linker namespace.
+ * ld_library_path and default_library_path represent the search path
+ * for the libraries in the namespace.
+ *
+ * The libraries in the namespace are searched by folowing order:
+ * 1. ld_library_path (Think of this as namespace-local LD_LIBRARY_PATH)
+ * 2. In directories specified by DT_RUNPATH of the "needed by" binary.
+ * 3. deault_library_path (This of this as namespace-local default library path)
+ *
+ * When type is ANDROID_NAMESPACE_TYPE_ISOLATED the resulting namespace requires all of
+ * the libraries to be on the search path or under the permitted_when_isolated_path;
+ * the search_path is ld_library_path:default_library_path. Note that the
+ * permitted_when_isolated_path path is not part of the search_path and
+ * does not affect the search order. It is a way to allow loading libraries from specific
+ * locations when using absolute path.
+ * If a library or any of its dependencies are outside of the permitted_when_isolated_path
+ * and search_path, and it is not part of the public namespace dlopen will fail.
+ */
+extern struct android_namespace_t* android_create_namespace(const char* name,
+                                                            const char* ld_library_path,
+                                                            const char* default_library_path,
+                                                            uint64_t type,
+                                                            const char* permitted_when_isolated_path);
+
+__END_DECLS
+
+#endif /* __ANDROID_DLEXT_NAMESPACES_H__ */
diff --git a/libnativeloader/native_loader.cpp b/libnativeloader/native_loader.cpp
index 33d5b62a4..bcc89e42e 100644
--- a/libnativeloader/native_loader.cpp
+++ b/libnativeloader/native_loader.cpp
@@ -19,7 +19,7 @@
 
 #include <dlfcn.h>
 #ifdef __ANDROID__
-#include <android/dlext.h>
+#include "dlext_namespaces.h"
 #include "cutils/properties.h"
 #include "log/log.h"
 #endif