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 extern bool android_link_namespaces(android_namespace_t* from,
95                                     android_namespace_t* to,
96                                     const char* shared_libs_sonames);
97 
98 extern void android_set_application_target_sdk_version(uint32_t target);
99 
100 __END_DECLS
101 
102 #endif /* __ANDROID_DLEXT_NAMESPACES_H__ */
103