1 /* 2 * Copyright (C) 2024 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 NATIVE_BRIDGE_SUPPORT_GUEST_STATE_DLEXT_NAMESPACES_H_ 18 #define NATIVE_BRIDGE_SUPPORT_GUEST_STATE_DLEXT_NAMESPACES_H_ 19 20 #include <android/dlext.h> 21 #include <stdbool.h> 22 #include <sys/cdefs.h> 23 24 __BEGIN_DECLS 25 26 enum { 27 /* A regular namespace is the namespace with a custom search path that does 28 * not impose any restrictions on the location of native libraries. 29 */ 30 ANDROID_NAMESPACE_TYPE_REGULAR = 0, 31 32 /* An isolated namespace requires all the libraries to be on the search path 33 * or under permitted_when_isolated_path. The search path is the union of 34 * ld_library_path and default_library_path. 35 */ 36 ANDROID_NAMESPACE_TYPE_ISOLATED = 1, 37 38 /* The shared namespace clones the list of libraries of the caller namespace upon creation 39 * which means that they are shared between namespaces - the caller namespace and the new one 40 * will use the same copy of a library if it was loaded prior to android_create_namespace call. 41 * 42 * Note that libraries loaded after the namespace is created will not be shared. 43 * 44 * Shared namespaces can be isolated or regular. Note that they do not inherit the search path nor 45 * permitted_path from the caller's namespace. 46 */ 47 ANDROID_NAMESPACE_TYPE_SHARED = 2, 48 49 /* This flag instructs linker to enable exempt-list workaround for the namespace. 50 * See http://b/26394120 for details. 51 */ 52 ANDROID_NAMESPACE_TYPE_EXEMPT_LIST_ENABLED = 0x08000000, 53 54 /* This flag instructs linker to use this namespace as the anonymous 55 * namespace. The anonymous namespace is used in the case when linker cannot 56 * identify the caller of dlopen/dlsym. This happens for the code not loaded 57 * by dynamic linker; for example calls from the mono-compiled code. There can 58 * be only one anonymous namespace in a process. If there already is an 59 * anonymous namespace in the process, using this flag when creating a new 60 * namespace causes an error. 61 */ 62 ANDROID_NAMESPACE_TYPE_ALSO_USED_AS_ANONYMOUS = 0x10000000, 63 64 ANDROID_NAMESPACE_TYPE_SHARED_ISOLATED = 65 ANDROID_NAMESPACE_TYPE_SHARED | ANDROID_NAMESPACE_TYPE_ISOLATED, 66 }; 67 68 /* 69 * Creates new linker namespace. 70 * ld_library_path and default_library_path represent the search path 71 * for the libraries in the namespace. 72 * 73 * The libraries in the namespace are searched by following order: 74 * 1. ld_library_path (Think of this as namespace-local LD_LIBRARY_PATH) 75 * 2. In directories specified by DT_RUNPATH of the "needed by" binary. 76 * 3. default_library_path (This of this as namespace-local default library path) 77 * 78 * When type is ANDROID_NAMESPACE_TYPE_ISOLATED the resulting namespace requires all of 79 * the libraries to be on the search path or under the permitted_when_isolated_path; 80 * the search_path is ld_library_path:default_library_path. Note that the 81 * permitted_when_isolated_path path is not part of the search_path and 82 * does not affect the search order. It is a way to allow loading libraries from specific 83 * locations when using absolute path. 84 * If a library or any of its dependencies are outside of the permitted_when_isolated_path 85 * and search_path, and it is not part of the public namespace dlopen will fail. 86 */ 87 extern struct android_namespace_t* android_create_namespace( 88 const char* name, const char* ld_library_path, const char* default_library_path, uint64_t type, 89 const char* permitted_when_isolated_path, struct android_namespace_t* parent); 90 91 /* 92 * Creates a link between namespaces. Every link has list of sonames of 93 * shared libraries. These are the libraries which are accessible from 94 * namespace 'from' but loaded within namespace 'to' context. 95 * When to namespace is nullptr this function establishes a link between 96 * 'from' namespace and the default namespace. 97 * 98 * The lookup order of the libraries in namespaces with links is following: 99 * 1. Look inside current namespace using 'this' namespace search path. 100 * 2. Look in linked namespaces 101 * 2.1. Perform soname check - if library soname is not in the list of shared 102 * libraries sonames skip this link, otherwise 103 * 2.2. Search library using linked namespace search path. Note that this 104 * step will not go deeper into linked namespaces for this library but 105 * will do so for DT_NEEDED libraries. 106 */ 107 extern bool android_link_namespaces(struct android_namespace_t* from, 108 struct android_namespace_t* to, 109 const char* shared_libs_sonames); 110 111 extern struct android_namespace_t* android_get_exported_namespace(const char* name); 112 113 __END_DECLS 114 115 #endif // NATIVE_BRIDGE_SUPPORT_GUEST_STATE_DLEXT_NAMESPACES_H_