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 #include "linker_mapped_file_fragment.h" 40 41 class ElfReader { 42 public: 43 ElfReader(); 44 45 bool Read(const char* name, int fd, off64_t file_offset, off64_t file_size); 46 bool Load(const android_dlextinfo* extinfo); 47 48 const char* name() const { return name_.c_str(); } 49 size_t phdr_count() const { return phdr_num_; } 50 ElfW(Addr) load_start() const { return reinterpret_cast<ElfW(Addr)>(load_start_); } 51 size_t load_size() const { return load_size_; } 52 ElfW(Addr) load_bias() const { return load_bias_; } 53 const ElfW(Phdr)* loaded_phdr() const { return loaded_phdr_; } 54 const ElfW(Dyn)* dynamic() const { return dynamic_; } 55 const char* get_string(ElfW(Word) index) const; 56 bool is_mapped_by_caller() const { return mapped_by_caller_; } 57 58 private: 59 bool ReadElfHeader(); 60 bool VerifyElfHeader(); 61 bool ReadProgramHeaders(); 62 bool ReadSectionHeaders(); 63 bool ReadDynamicSection(); 64 bool ReserveAddressSpace(const android_dlextinfo* extinfo); 65 bool LoadSegments(); 66 bool FindPhdr(); 67 bool CheckPhdr(ElfW(Addr)); 68 bool CheckFileRange(ElfW(Addr) offset, size_t size, size_t alignment); 69 70 bool did_read_; 71 bool did_load_; 72 std::string name_; 73 int fd_; 74 off64_t file_offset_; 75 off64_t file_size_; 76 77 ElfW(Ehdr) header_; 78 size_t phdr_num_; 79 80 MappedFileFragment phdr_fragment_; 81 const ElfW(Phdr)* phdr_table_; 82 83 MappedFileFragment shdr_fragment_; 84 const ElfW(Shdr)* shdr_table_; 85 size_t shdr_num_; 86 87 MappedFileFragment dynamic_fragment_; 88 const ElfW(Dyn)* dynamic_; 89 90 MappedFileFragment strtab_fragment_; 91 const char* strtab_; 92 size_t strtab_size_; 93 94 // First page of reserved address space. 95 void* load_start_; 96 // Size in bytes of reserved address space. 97 size_t load_size_; 98 // Load bias. 99 ElfW(Addr) load_bias_; 100 101 // Loaded phdr. 102 const ElfW(Phdr)* loaded_phdr_; 103 104 // Is map owned by the caller 105 bool mapped_by_caller_; 106 }; 107 108 size_t phdr_table_get_load_size(const ElfW(Phdr)* phdr_table, size_t phdr_count, 109 ElfW(Addr)* min_vaddr = nullptr, ElfW(Addr)* max_vaddr = nullptr); 110 111 int phdr_table_protect_segments(const ElfW(Phdr)* phdr_table, 112 size_t phdr_count, ElfW(Addr) load_bias); 113 114 int phdr_table_unprotect_segments(const ElfW(Phdr)* phdr_table, size_t phdr_count, 115 ElfW(Addr) load_bias); 116 117 int phdr_table_protect_gnu_relro(const ElfW(Phdr)* phdr_table, size_t phdr_count, 118 ElfW(Addr) load_bias); 119 120 int phdr_table_serialize_gnu_relro(const ElfW(Phdr)* phdr_table, size_t phdr_count, 121 ElfW(Addr) load_bias, int fd); 122 123 int phdr_table_map_gnu_relro(const ElfW(Phdr)* phdr_table, size_t phdr_count, 124 ElfW(Addr) load_bias, int fd); 125 126 #if defined(__arm__) 127 int phdr_table_get_arm_exidx(const ElfW(Phdr)* phdr_table, size_t phdr_count, ElfW(Addr) load_bias, 128 ElfW(Addr)** arm_exidx, size_t* arm_exidix_count); 129 #endif 130 131 void phdr_table_get_dynamic_section(const ElfW(Phdr)* phdr_table, size_t phdr_count, 132 ElfW(Addr) load_bias, ElfW(Dyn)** dynamic, 133 ElfW(Word)* dynamic_flags); 134 135 const char* phdr_table_get_interpreter_name(const ElfW(Phdr) * phdr_table, size_t phdr_count, 136 ElfW(Addr) load_bias); 137 138 #endif /* LINKER_PHDR_H */ 139
