1 /* 2 * Copyright (C) 2016 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef ART_LIBNATIVELOADER_INCLUDE_NATIVELOADER_DLEXT_NAMESPACES_H_ 18 #define ART_LIBNATIVELOADER_INCLUDE_NATIVELOADER_DLEXT_NAMESPACES_H_ 19 20 #include <android/dlext.h> 21 #include <stdbool.h> 22 23 __BEGIN_DECLS 24 25 enum { 26 /* A regular namespace is the namespace with a custom search path that does 27 * not impose any restrictions on the location of native libraries. 28 */ 29 ANDROID_NAMESPACE_TYPE_REGULAR = 0, 30 31 /* An isolated namespace requires all the libraries to be on the search path 32 * or under permitted_when_isolated_path. The search path is the union of 33 * ld_library_path and default_library_path. 34 */ 35 ANDROID_NAMESPACE_TYPE_ISOLATED = 1, 36 37 /* The shared namespace clones the list of libraries of the caller namespace upon creation 38 * which means that they are shared between namespaces - the caller namespace and the new one 39 * will use the same copy of a library if it was loaded prior to android_create_namespace call. 40 * 41 * Note that libraries loaded after the namespace is created will not be shared. 42 * 43 * Shared namespaces can be isolated or regular. Note that they do not inherit the search path nor 44 * permitted_path from the caller's namespace. 45 */ 46 ANDROID_NAMESPACE_TYPE_SHARED = 2, 47 48 /* This flag instructs linker to enable exempt-list workaround for the namespace. 49 * See http://b/26394120 for details. 50 */ 51 ANDROID_NAMESPACE_TYPE_EXEMPT_LIST_ENABLED = 0x08000000, 52 53 /* This flag instructs linker to use this namespace as the anonymous 54 * namespace. The anonymous namespace is used in the case when linker cannot 55 * identify the caller of dlopen/dlsym. This happens for the code not loaded 56 * by dynamic linker; for example calls from the mono-compiled code. There can 57 * be only one anonymous namespace in a process. If there already is an 58 * anonymous namespace in the process, using this flag when creating a new 59 * namespace causes an error. 60 */ 61 ANDROID_NAMESPACE_TYPE_ALSO_USED_AS_ANONYMOUS = 0x10000000, 62 63 ANDROID_NAMESPACE_TYPE_SHARED_ISOLATED = 64 ANDROID_NAMESPACE_TYPE_SHARED | ANDROID_NAMESPACE_TYPE_ISOLATED, 65 }; 66 67 /* 68 * Creates new linker namespace. 69 * ld_library_path and default_library_path represent the search path 70 * for the libraries in the namespace. 71 * 72 * The libraries in the namespace are searched by folowing order: 73 * 1. ld_library_path (Think of this as namespace-local LD_LIBRARY_PATH) 74 * 2. In directories specified by DT_RUNPATH of the "needed by" binary. 75 * 3. deault_library_path (This of this as namespace-local default library path) 76 * 77 * When type is ANDROID_NAMESPACE_TYPE_ISOLATED the resulting namespace requires all of 78 * the libraries to be on the search path or under the permitted_when_isolated_path; 79 * the search_path is ld_library_path:default_library_path. Note that the 80 * permitted_when_isolated_path path is not part of the search_path and 81 * does not affect the search order. It is a way to allow loading libraries from specific 82 * locations when using absolute path. 83 * If a library or any of its dependencies are outside of the permitted_when_isolated_path 84 * and search_path, and it is not part of the public namespace dlopen will fail. 85 */ 86 extern struct android_namespace_t* android_create_namespace( 87 const char* name, const char* ld_library_path, const char* default_library_path, uint64_t type, 88 const char* permitted_when_isolated_path, struct android_namespace_t* parent); 89 90 /* 91 * Creates a link between namespaces. Every link has list of sonames of 92 * shared libraries. These are the libraries which are accessible from 93 * namespace 'from' but loaded within namespace 'to' context. 94 * When to namespace is nullptr this function establishes a link between 95 * 'from' namespace and the default namespace. 96 * 97 * The lookup order of the libraries in namespaces with links is following: 98 * 1. Look inside current namespace using 'this' namespace search path. 99 * 2. Look in linked namespaces 100 * 2.1. Perform soname check - if library soname is not in the list of shared 101 * libraries sonames skip this link, otherwise 102 * 2.2. Search library using linked namespace search path. Note that this 103 * step will not go deeper into linked namespaces for this library but 104 * will do so for DT_NEEDED libraries. 105 */ 106 extern bool android_link_namespaces(struct android_namespace_t* from, 107 struct android_namespace_t* to, 108 const char* shared_libs_sonames); 109 110 extern struct android_namespace_t* android_get_exported_namespace(const char* name); 111 112 __END_DECLS 113 114 #endif // ART_LIBNATIVELOADER_INCLUDE_NATIVELOADER_DLEXT_NAMESPACES_H_ 115