dlext.h revision 702ab5b37e77684ee352300d32b078606ee388d0 
1/*
2 * Copyright (C) 2014 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_H__
18#define __ANDROID_DLEXT_H__
19
20#include <stddef.h>
21#include <sys/cdefs.h>
22
23__BEGIN_DECLS
24
25/* bitfield definitions for android_dlextinfo.flags */
26enum {
27  /* When set, the reserved_addr and reserved_size fields must point to an
28   * already-reserved region of address space which will be used to load the
29   * library if it fits. If the reserved region is not large enough, the load
30   * will fail.
31   */
32  ANDROID_DLEXT_RESERVED_ADDRESS      = 0x1,
33
34  /* As DLEXT_RESERVED_ADDRESS, but if the reserved region is not large enough,
35   * the linker will choose an available address instead.
36   */
37  ANDROID_DLEXT_RESERVED_ADDRESS_HINT = 0x2,
38
39  /* When set, write the GNU RELRO section of the mapped library to relro_fd
40   * after relocation has been performed, to allow it to be reused by another
41   * process loading the same library at the same address. This implies
42   * ANDROID_DLEXT_USE_RELRO.
43   */
44  ANDROID_DLEXT_WRITE_RELRO           = 0x4,
45
46  /* When set, compare the GNU RELRO section of the mapped library to relro_fd
47   * after relocation has been performed, and replace any relocated pages that
48   * are identical with a version mapped from the file.
49   */
50  ANDROID_DLEXT_USE_RELRO             = 0x8,
51
52  /* Instruct dlopen to use library_fd instead of opening file by name.
53   * The filename parameter is still used to identify the library.
54   */
55  ANDROID_DLEXT_USE_LIBRARY_FD        = 0x10,
56
57  /* If opening a library using library_fd read it starting at library_fd_offset.
58   * This flag is only valid when ANDROID_DLEXT_USE_LIBRARY_FD is set.
59   */
60
61  ANDROID_DLEXT_USE_LIBRARY_FD_OFFSET    = 0x20,
62
63  /* Mask of valid bits */
64  ANDROID_DLEXT_VALID_FLAG_BITS       = ANDROID_DLEXT_RESERVED_ADDRESS |
65                                        ANDROID_DLEXT_RESERVED_ADDRESS_HINT |
66                                        ANDROID_DLEXT_WRITE_RELRO |
67                                        ANDROID_DLEXT_USE_RELRO |
68                                        ANDROID_DLEXT_USE_LIBRARY_FD |
69                                        ANDROID_DLEXT_USE_LIBRARY_FD_OFFSET,
70};
71
72typedef struct {
73  uint64_t flags;
74  void*   reserved_addr;
75  size_t  reserved_size;
76  int     relro_fd;
77  int     library_fd;
78  off64_t library_fd_offset;
79} android_dlextinfo;
80
81extern void* android_dlopen_ext(const char* filename, int flag, const android_dlextinfo* extinfo);
82
83__END_DECLS
84
85#endif /* __ANDROID_DLEXT_H__ */
86