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 22 __BEGIN_DECLS 23 24 /* 25 * Initializes anonymous namespaces. The shared_libs_sonames is the list of sonames 26 * to be shared by default namespace separated by colon. Example: "libc.so:libm.so:libdl.so". 27 * 28 * The library_search_path is the search path for anonymous namespace. The anonymous namespace 29 * is used in the case when linker cannot identify the caller of dlopen/dlsym. This happens 30 * for the code not loaded by dynamic linker; for example calls from the mono-compiled code. 31 */ 32 extern bool android_init_anonymous_namespace(const char* shared_libs_sonames, 33 const char* library_search_path); 34 35 36 enum { 37 /* A regular namespace is the namespace with a custom search path that does 38 * not impose any restrictions on the location of native libraries. 39 */ 40 ANDROID_NAMESPACE_TYPE_REGULAR = 0, 41 42 /* An isolated namespace requires all the libraries to be on the search path 43 * or under permitted_when_isolated_path. The search path is the union of 44 * ld_library_path and default_library_path. 45 */ 46 ANDROID_NAMESPACE_TYPE_ISOLATED = 1, 47 48 /* The shared namespace clones the list of libraries of the caller namespace upon creation 49 * which means that they are shared between namespaces - the caller namespace and the new one 50 * will use the same copy of a library if it was loaded prior to android_create_namespace call. 51 * 52 * Note that libraries loaded after the namespace is created will not be shared. 53 * 54 * Shared namespaces can be isolated or regular. Note that they do not inherit the search path nor 55 * permitted_path from the caller's namespace. 56 */ 57 ANDROID_NAMESPACE_TYPE_SHARED = 2, 58 59 /* This flag instructs linker to enable grey-list workaround for the namespace. 60 * See http://b/26394120 for details. 61 */ 62 ANDROID_NAMESPACE_TYPE_GREYLIST_ENABLED = 0x08000000, 63 64 ANDROID_NAMESPACE_TYPE_SHARED_ISOLATED = ANDROID_NAMESPACE_TYPE_SHARED | 65 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 folowing 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. deault_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(const char* name, 88 const char* ld_library_path, 89 const char* default_library_path, 90 uint64_t type, 91 const char* permitted_when_isolated_path, 92 android_namespace_t* parent); 93 94 /* 95 * Creates a link between namespaces. Every link has list of sonames of 96 * shared libraries. These are the libraries which are accessible from 97 * namespace 'from' but loaded within namespace 'to' context. 98 * When to namespace is nullptr this function establishes a link between 99 * 'from' namespace and the default namespace. 100 * 101 * The lookup order of the libraries in namespaces with links is following: 102 * 1. Look inside current namespace using 'this' namespace search path. 103 * 2. Look in linked namespaces 104 * 2.1. Perform soname check - if library soname is not in the list of shared 105 * libraries sonames skip this link, otherwise 106 * 2.2. Search library using linked namespace search path. Note that this 107 * step will not go deeper into linked namespaces for this library but 108 * will do so for DT_NEEDED libraries. 109 */ 110 extern bool android_link_namespaces(android_namespace_t* from, 111 android_namespace_t* to, 112 const char* shared_libs_sonames); 113 114 /* 115 * Get the default library search path. 116 * The path will be copied into buffer, which must have space for at least 117 * buffer_size chars. Elements are separated with ':', and the path will always 118 * be null-terminated. 119 * 120 * If buffer_size is too small to hold the entire default search path and the 121 * null terminator, this function will abort. There is currently no way to find 122 * out what the required buffer size is. At the time of this writing, PATH_MAX 123 * is sufficient and used by all callers of this function. 124 */ 125 extern void android_get_LD_LIBRARY_PATH(char* buffer, size_t buffer_size); 126 127 extern android_namespace_t* android_get_exported_namespace(const char* name); 128 129 __END_DECLS 130 131 #endif /* __ANDROID_DLEXT_NAMESPACES_H__ */ 132
