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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 public and anonymous namespaces. The public_ns_sonames is the list of sonames
26  * to be included into public namespace separated by colon. Example: "libc.so:libm.so:libdl.so".
27  * The libraries in this list should be loaded prior to this call.
28  *
29  * The anon_ns_library_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_namespaces(const char* public_ns_sonames,
34                                     const char* anon_ns_library_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   ANDROID_NAMESPACE_TYPE_SHARED_ISOLATED = ANDROID_NAMESPACE_TYPE_SHARED |
60                                            ANDROID_NAMESPACE_TYPE_ISOLATED,
61 };
62 
63 /*
64  * Creates new linker namespace.
65  * ld_library_path and default_library_path represent the search path
66  * for the libraries in the namespace.
67  *
68  * The libraries in the namespace are searched by folowing order:
69  * 1. ld_library_path (Think of this as namespace-local LD_LIBRARY_PATH)
70  * 2. In directories specified by DT_RUNPATH of the "needed by" binary.
71  * 3. deault_library_path (This of this as namespace-local default library path)
72  *
73  * When type is ANDROID_NAMESPACE_TYPE_ISOLATED the resulting namespace requires all of
74  * the libraries to be on the search path or under the permitted_when_isolated_path;
75  * the search_path is ld_library_path:default_library_path. Note that the
76  * permitted_when_isolated_path path is not part of the search_path and
77  * does not affect the search order. It is a way to allow loading libraries from specific
78  * locations when using absolute path.
79  * If a library or any of its dependencies are outside of the permitted_when_isolated_path
80  * and search_path, and it is not part of the public namespace dlopen will fail.
81  */
82 extern struct android_namespace_t* android_create_namespace(const char* name,
83                                                             const char* ld_library_path,
84                                                             const char* default_library_path,
85                                                             uint64_t type,
86                                                             const char* permitted_when_isolated_path,
87                                                             android_namespace_t* parent);
88 
89 extern void android_set_application_target_sdk_version(uint32_t target);
90 
91 __END_DECLS
92 
93 #endif /* __ANDROID_DLEXT_NAMESPACES_H__ */
94