Replace public library list with shared lib sonames (part 2/2)

This commit updates interface of libdl.c.

1. android_init_namespaces is replaces with android_init_anonymous_namespace
2. added 2 arguments to android_create_namespace to specify linked namespace
   and the list of shared libraries sonames.
3. symbol lookup does not get past boundary libraries (added check and test for it).

Bug: http://b/26833548
Bug: http://b/21879602
Test: bionic-unit-tests --gtest_filter=dl*:Dl*
Change-Id: I32921da487a02e5bd0d2fc528904d1228394bfb9
diff --git a/libdl/libdl.c b/libdl/libdl.c
index 3fbd7e5..6a95629 100644
--- a/libdl/libdl.c
+++ b/libdl/libdl.c
@@ -72,8 +72,8 @@
 uint32_t __loader_android_get_application_target_sdk_version();
 
 __attribute__((__weak__, visibility("default")))
-bool __loader_android_init_namespaces(const char* public_ns_sonames,
-                                      const char* anon_ns_library_path);
+bool __loader_android_init_anonymous_namespace(const char* shared_libs_sonames,
+                                               const char* library_search_path);
 
 __attribute__((__weak__, visibility("default")))
 struct android_namespace_t* __loader_android_create_namespace(
@@ -86,6 +86,12 @@
                                 const void* caller_addr);
 
 __attribute__((__weak__, visibility("default")))
+bool __loader_android_link_namespaces(
+                                struct android_namespace_t* namespace_from,
+                                struct android_namespace_t* namespace_to,
+                                const char* shared_libs_sonames);
+
+__attribute__((__weak__, visibility("default")))
 void __loader_android_dlwarning(void* obj, void (*f)(void*, const char*));
 
 // Proxy calls to bionic loader
@@ -146,9 +152,9 @@
   return __loader_android_get_application_target_sdk_version();
 }
 
-bool android_init_namespaces(const char* public_ns_sonames,
-                             const char* anon_ns_library_path) {
-  return __loader_android_init_namespaces(public_ns_sonames, anon_ns_library_path);
+bool android_init_anonymous_namespace(const char* shared_libs_sonames,
+                                      const char* library_search_path) {
+  return __loader_android_init_anonymous_namespace(shared_libs_sonames, library_search_path);
 }
 
 struct android_namespace_t* android_create_namespace(const char* name,
@@ -167,6 +173,12 @@
                                            caller_addr);
 }
 
+bool android_link_namespaces(struct android_namespace_t* namespace_from,
+                             struct android_namespace_t* namespace_to,
+                             const char* shared_libs_sonames) {
+  return __loader_android_link_namespaces(namespace_from, namespace_to, shared_libs_sonames);
+}
+
 void android_dlwarning(void* obj, void (*f)(void*, const char*)) {
   __loader_android_dlwarning(obj, f);
 }