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 __ANDROID_DLEXT_NAMESPACES_H__ 18 #define __ANDROID_DLEXT_NAMESPACES_H__ 19 20 #include <android/dlext.h> 21 #include <stdbool.h> 22 23 __BEGIN_DECLS 24 25 /* 26 * Initializes anonymous namespaces. The shared_libs_sonames is the list of sonames 27 * to be shared by default namespace separated by colon. Example: "libc.so:libm.so:libdl.so". 28 * 29 * The library_search_path is the search path for anonymous namespace. The anonymous namespace 30 * is used in the case when linker cannot identify the caller of dlopen/dlsym. This happens 31 * for the code not loaded by dynamic linker; for example calls from the mono-compiled code. 32 */ 33 extern bool android_init_anonymous_namespace(const char* shared_libs_sonames, 34 const char* library_search_path); 35 36 37 enum { 38 /* A regular namespace is the namespace with a custom search path that does 39 * not impose any restrictions on the location of native libraries. 40 */ 41 ANDROID_NAMESPACE_TYPE_REGULAR = 0, 42 43 /* An isolated namespace requires all the libraries to be on the search path 44 * or under permitted_when_isolated_path. The search path is the union of 45 * ld_library_path and default_library_path. 46 */ 47 ANDROID_NAMESPACE_TYPE_ISOLATED = 1, 48 49 /* The shared namespace clones the list of libraries of the caller namespace upon creation 50 * which means that they are shared between namespaces - the caller namespace and the new one 51 * will use the same copy of a library if it was loaded prior to android_create_namespace call. 52 * 53 * Note that libraries loaded after the namespace is created will not be shared. 54 * 55 * Shared namespaces can be isolated or regular. Note that they do not inherit the search path nor 56 * permitted_path from the caller's namespace. 57 */ 58 ANDROID_NAMESPACE_TYPE_SHARED = 2, 59 60 /* This flag instructs linker to enable grey-list workaround for the namespace. 61 * See http://b/26394120 for details. 62 */ 63 ANDROID_NAMESPACE_TYPE_GREYLIST_ENABLED = 0x08000000, 64 65 ANDROID_NAMESPACE_TYPE_SHARED_ISOLATED = ANDROID_NAMESPACE_TYPE_SHARED | 66 ANDROID_NAMESPACE_TYPE_ISOLATED, 67 }; 68 69 /* 70 * Creates new linker namespace. 71 * ld_library_path and default_library_path represent the search path 72 * for the libraries in the namespace. 73 * 74 * The libraries in the namespace are searched by folowing order: 75 * 1. ld_library_path (Think of this as namespace-local LD_LIBRARY_PATH) 76 * 2. In directories specified by DT_RUNPATH of the "needed by" binary. 77 * 3. deault_library_path (This of this as namespace-local default library path) 78 * 79 * When type is ANDROID_NAMESPACE_TYPE_ISOLATED the resulting namespace requires all of 80 * the libraries to be on the search path or under the permitted_when_isolated_path; 81 * the search_path is ld_library_path:default_library_path. Note that the 82 * permitted_when_isolated_path path is not part of the search_path and 83 * does not affect the search order. It is a way to allow loading libraries from specific 84 * locations when using absolute path. 85 * If a library or any of its dependencies are outside of the permitted_when_isolated_path 86 * and search_path, and it is not part of the public namespace dlopen will fail. 87 */ 88 extern struct android_namespace_t* android_create_namespace( 89 const char* name, const char* ld_library_path, const char* default_library_path, uint64_t type, 90 const char* permitted_when_isolated_path, struct android_namespace_t* parent); 91 92 /* 93 * Creates a link between namespaces. Every link has list of sonames of 94 * shared libraries. These are the libraries which are accessible from 95 * namespace 'from' but loaded within namespace 'to' context. 96 * When to namespace is nullptr this function establishes a link between 97 * 'from' namespace and the default namespace. 98 * 99 * The lookup order of the libraries in namespaces with links is following: 100 * 1. Look inside current namespace using 'this' namespace search path. 101 * 2. Look in linked namespaces 102 * 2.1. Perform soname check - if library soname is not in the list of shared 103 * libraries sonames skip this link, otherwise 104 * 2.2. Search library using linked namespace search path. Note that this 105 * step will not go deeper into linked namespaces for this library but 106 * will do so for DT_NEEDED libraries. 107 */ 108 extern bool android_link_namespaces(struct android_namespace_t* from, 109 struct android_namespace_t* to, 110 const char* shared_libs_sonames); 111 112 extern struct android_namespace_t* android_get_exported_namespace(const char* name); 113 114 __END_DECLS 115 116 #endif /* __ANDROID_DLEXT_NAMESPACES_H__ */ 117