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 30 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 */ 37 38 #include "linker.h" 39 40 class ElfReader { 41 public: 42 ElfReader(const char* name, int fd); 43 ~ElfReader(); 44 45 bool Load(); 46 phdr_count()47 size_t phdr_count() { return phdr_num_; } load_start()48 Elf32_Addr load_start() { return reinterpret_cast<Elf32_Addr>(load_start_); } load_size()49 Elf32_Addr load_size() { return load_size_; } load_bias()50 Elf32_Addr load_bias() { return load_bias_; } loaded_phdr()51 const Elf32_Phdr* loaded_phdr() { return loaded_phdr_; } 52 53 private: 54 bool ReadElfHeader(); 55 bool VerifyElfHeader(); 56 bool ReadProgramHeader(); 57 bool ReserveAddressSpace(); 58 bool LoadSegments(); 59 bool FindPhdr(); 60 bool CheckPhdr(Elf32_Addr); 61 62 const char* name_; 63 int fd_; 64 65 Elf32_Ehdr header_; 66 size_t phdr_num_; 67 68 void* phdr_mmap_; 69 Elf32_Phdr* phdr_table_; 70 Elf32_Addr phdr_size_; 71 72 // First page of reserved address space. 73 void* load_start_; 74 // Size in bytes of reserved address space. 75 Elf32_Addr load_size_; 76 // Load bias. 77 Elf32_Addr load_bias_; 78 79 // Loaded phdr. 80 const Elf32_Phdr* loaded_phdr_; 81 }; 82 83 Elf32_Addr phdr_table_get_load_size(const Elf32_Phdr* phdr, size_t phnum); 84 85 int 86 phdr_table_protect_segments(const Elf32_Phdr* phdr_table, 87 int phdr_count, 88 Elf32_Addr load_bias); 89 90 int 91 phdr_table_unprotect_segments(const Elf32_Phdr* phdr_table, 92 int phdr_count, 93 Elf32_Addr load_bias); 94 95 int 96 phdr_table_protect_gnu_relro(const Elf32_Phdr* phdr_table, 97 int phdr_count, 98 Elf32_Addr load_bias); 99 100 101 #ifdef ANDROID_ARM_LINKER 102 int 103 phdr_table_get_arm_exidx(const Elf32_Phdr* phdr_table, 104 int phdr_count, 105 Elf32_Addr load_bias, 106 Elf32_Addr** arm_exidx, 107 unsigned* arm_exidix_count); 108 #endif 109 110 void 111 phdr_table_get_dynamic_section(const Elf32_Phdr* phdr_table, 112 int phdr_count, 113 Elf32_Addr load_bias, 114 Elf32_Dyn** dynamic, 115 size_t* dynamic_count, 116 Elf32_Word* dynamic_flags); 117 118 #endif /* LINKER_PHDR_H */ 119