1 /* 2 * Copyright (C) 2008 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 29 #ifndef _LINKER_H_ 30 #define _LINKER_H_ 31 32 #include <unistd.h> 33 #include <sys/types.h> 34 #include <elf.h> 35 #include <sys/exec_elf.h> 36 37 #include <link.h> 38 39 #include "private/libc_logging.h" 40 41 #define DL_ERR(fmt, x...) \ 42 do { \ 43 __libc_format_buffer(linker_get_error_buffer(), linker_get_error_buffer_size(), fmt, ##x); \ 44 /* If LD_DEBUG is set high enough, log every dlerror(3) message. */ \ 45 DEBUG("%s\n", linker_get_error_buffer()); \ 46 } while(0) 47 48 // Returns the address of the page containing address 'x'. 49 #define PAGE_START(x) ((x) & PAGE_MASK) 50 51 // Returns the offset of address 'x' in its page. 52 #define PAGE_OFFSET(x) ((x) & ~PAGE_MASK) 53 54 // Returns the address of the next page after address 'x', unless 'x' is 55 // itself at the start of a page. 56 #define PAGE_END(x) PAGE_START((x) + (PAGE_SIZE-1)) 57 58 // Magic shared structures that GDB knows about. 59 60 struct link_map_t { 61 uintptr_t l_addr; 62 char* l_name; 63 uintptr_t l_ld; 64 link_map_t* l_next; 65 link_map_t* l_prev; 66 }; 67 68 // Values for r_debug->state 69 enum { 70 RT_CONSISTENT, 71 RT_ADD, 72 RT_DELETE 73 }; 74 75 struct r_debug { 76 int32_t r_version; 77 link_map_t* r_map; 78 void (*r_brk)(void); 79 int32_t r_state; 80 uintptr_t r_ldbase; 81 }; 82 83 #define FLAG_LINKED 0x00000001 84 #define FLAG_EXE 0x00000004 // The main executable 85 #define FLAG_LINKER 0x00000010 // The linker itself 86 87 #define SOINFO_NAME_LEN 128 88 89 typedef void (*linker_function_t)(); 90 91 struct soinfo { 92 public: 93 char name[SOINFO_NAME_LEN]; 94 const Elf32_Phdr* phdr; 95 size_t phnum; 96 Elf32_Addr entry; 97 Elf32_Addr base; 98 unsigned size; 99 100 uint32_t unused1; // DO NOT USE, maintained for compatibility. 101 102 Elf32_Dyn* dynamic; 103 104 uint32_t unused2; // DO NOT USE, maintained for compatibility 105 uint32_t unused3; // DO NOT USE, maintained for compatibility 106 107 soinfo* next; 108 unsigned flags; 109 110 const char* strtab; 111 Elf32_Sym* symtab; 112 113 size_t nbucket; 114 size_t nchain; 115 unsigned* bucket; 116 unsigned* chain; 117 118 unsigned* plt_got; 119 120 Elf32_Rel* plt_rel; 121 size_t plt_rel_count; 122 123 Elf32_Rel* rel; 124 size_t rel_count; 125 126 linker_function_t* preinit_array; 127 size_t preinit_array_count; 128 129 linker_function_t* init_array; 130 size_t init_array_count; 131 linker_function_t* fini_array; 132 size_t fini_array_count; 133 134 linker_function_t init_func; 135 linker_function_t fini_func; 136 137 #if defined(ANDROID_ARM_LINKER) 138 // ARM EABI section used for stack unwinding. 139 unsigned* ARM_exidx; 140 size_t ARM_exidx_count; 141 #elif defined(ANDROID_MIPS_LINKER) 142 unsigned mips_symtabno; 143 unsigned mips_local_gotno; 144 unsigned mips_gotsym; 145 #endif 146 147 size_t ref_count; 148 link_map_t link_map; 149 150 bool constructors_called; 151 152 // When you read a virtual address from the ELF file, add this 153 // value to get the corresponding address in the process' address space. 154 Elf32_Addr load_bias; 155 156 bool has_text_relocations; 157 bool has_DT_SYMBOLIC; 158 159 void CallConstructors(); 160 void CallDestructors(); 161 void CallPreInitConstructors(); 162 163 private: 164 void CallArray(const char* array_name, linker_function_t* functions, size_t count, bool reverse); 165 void CallFunction(const char* function_name, linker_function_t function); 166 }; 167 168 extern soinfo libdl_info; 169 170 // These aren't defined in <sys/exec_elf.h>. 171 #ifndef DT_PREINIT_ARRAY 172 #define DT_PREINIT_ARRAY 32 173 #endif 174 #ifndef DT_PREINIT_ARRAYSZ 175 #define DT_PREINIT_ARRAYSZ 33 176 #endif 177 178 void do_android_update_LD_LIBRARY_PATH(const char* ld_library_path); 179 soinfo* do_dlopen(const char* name, int flags); 180 int do_dlclose(soinfo* si); 181 182 Elf32_Sym* dlsym_linear_lookup(const char* name, soinfo** found, soinfo* start); 183 soinfo* find_containing_library(const void* addr); 184 185 Elf32_Sym* dladdr_find_symbol(soinfo* si, const void* addr); 186 Elf32_Sym* dlsym_handle_lookup(soinfo* si, const char* name); 187 188 void debuggerd_init(); 189 extern "C" abort_msg_t* gAbortMessage; 190 extern "C" void notify_gdb_of_libraries(); 191 192 char* linker_get_error_buffer(); 193 size_t linker_get_error_buffer_size(); 194 195 #endif 196
