1 /*
2 * Copyright (C) 2012 The Android Open Source Project
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * * Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * * Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in
12 * the documentation and/or other materials provided with the
13 * distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28 #ifndef LINKER_PHDR_H
29 #define LINKER_PHDR_H
31 /* Declarations related to the ELF program header table and segments.
32 *
33 * The design goal is to provide an API that is as close as possible
34 * to the ELF spec, and does not depend on linker-specific data
35 * structures (e.g. the exact layout of struct soinfo).
36 */
38 #include "linker.h"
40 class ElfReader {
41 public:
42 ElfReader(const char* name, int fd);
43 ~ElfReader();
45 bool Load(const android_dlextinfo* extinfo);
47 size_t phdr_count() { return phdr_num_; }
48 ElfW(Addr) load_start() { return reinterpret_cast<ElfW(Addr)>(load_start_); }
49 size_t load_size() { return load_size_; }
50 ElfW(Addr) load_bias() { return load_bias_; }
51 const ElfW(Phdr)* loaded_phdr() { return loaded_phdr_; }
53 private:
54 bool ReadElfHeader();
55 bool VerifyElfHeader();
56 bool ReadProgramHeader();
57 bool ReserveAddressSpace(const android_dlextinfo* extinfo);
58 bool LoadSegments();
59 bool FindPhdr();
60 bool CheckPhdr(ElfW(Addr));
62 const char* name_;
63 int fd_;
65 ElfW(Ehdr) header_;
66 size_t phdr_num_;
68 void* phdr_mmap_;
69 ElfW(Phdr)* phdr_table_;
70 ElfW(Addr) phdr_size_;
72 // First page of reserved address space.
73 void* load_start_;
74 // Size in bytes of reserved address space.
75 size_t load_size_;
76 // Load bias.
77 ElfW(Addr) load_bias_;
79 // Loaded phdr.
80 const ElfW(Phdr)* loaded_phdr_;
81 };
83 size_t phdr_table_get_load_size(const ElfW(Phdr)* phdr_table, size_t phdr_count,
84 ElfW(Addr)* min_vaddr = nullptr, ElfW(Addr)* max_vaddr = nullptr);
86 int phdr_table_protect_segments(const ElfW(Phdr)* phdr_table, size_t phdr_count, ElfW(Addr) load_bias);
88 int phdr_table_unprotect_segments(const ElfW(Phdr)* phdr_table, size_t phdr_count, ElfW(Addr) load_bias);
90 int phdr_table_protect_gnu_relro(const ElfW(Phdr)* phdr_table, size_t phdr_count, ElfW(Addr) load_bias);
92 int phdr_table_serialize_gnu_relro(const ElfW(Phdr)* phdr_table, size_t phdr_count, ElfW(Addr) load_bias,
93 int fd);
95 int phdr_table_map_gnu_relro(const ElfW(Phdr)* phdr_table, size_t phdr_count, ElfW(Addr) load_bias,
96 int fd);
98 #if defined(__arm__)
99 int phdr_table_get_arm_exidx(const ElfW(Phdr)* phdr_table, size_t phdr_count, ElfW(Addr) load_bias,
100 ElfW(Addr)** arm_exidx, unsigned* arm_exidix_count);
101 #endif
103 void phdr_table_get_dynamic_section(const ElfW(Phdr)* phdr_table, size_t phdr_count,
104 ElfW(Addr) load_bias, ElfW(Dyn)** dynamic,
105 ElfW(Word)* dynamic_flags);
107 #endif /* LINKER_PHDR_H */