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