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 (false) 47 48 #define DL_WARN(fmt, x...) \ 49 do { \ 50 __libc_format_log(ANDROID_LOG_WARN, "linker", fmt, ##x); \ 51 __libc_format_fd(2, "WARNING: linker: "); \ 52 __libc_format_fd(2, fmt, ##x); \ 53 __libc_format_fd(2, "\n"); \ 54 } while (false) 55 56 57 // Returns the address of the page containing address 'x'. 58 #define PAGE_START(x) ((x) & PAGE_MASK) 59 60 // Returns the offset of address 'x' in its page. 61 #define PAGE_OFFSET(x) ((x) & ~PAGE_MASK) 62 63 // Returns the address of the next page after address 'x', unless 'x' is 64 // itself at the start of a page. 65 #define PAGE_END(x) PAGE_START((x) + (PAGE_SIZE-1)) 66 67 // Magic shared structures that GDB knows about. 68 69 struct link_map_t { 70 uintptr_t l_addr; 71 char* l_name; 72 uintptr_t l_ld; 73 link_map_t* l_next; 74 link_map_t* l_prev; 75 }; 76 77 // Values for r_debug->state 78 enum { 79 RT_CONSISTENT, 80 RT_ADD, 81 RT_DELETE 82 }; 83 84 struct r_debug { 85 int32_t r_version; 86 link_map_t* r_map; 87 void (*r_brk)(void); 88 int32_t r_state; 89 uintptr_t r_ldbase; 90 }; 91 92 #define FLAG_LINKED 0x00000001 93 #define FLAG_EXE 0x00000004 // The main executable 94 #define FLAG_LINKER 0x00000010 // The linker itself 95 96 #define SOINFO_NAME_LEN 128 97 98 typedef void (*linker_function_t)(); 99 100 struct soinfo { 101 public: 102 char name[SOINFO_NAME_LEN]; 103 const Elf32_Phdr* phdr; 104 size_t phnum; 105 Elf32_Addr entry; 106 Elf32_Addr base; 107 unsigned size; 108 109 uint32_t unused1; // DO NOT USE, maintained for compatibility. 110 111 Elf32_Dyn* dynamic; 112 113 uint32_t unused2; // DO NOT USE, maintained for compatibility 114 uint32_t unused3; // DO NOT USE, maintained for compatibility 115 116 soinfo* next; 117 unsigned flags; 118 119 const char* strtab; 120 Elf32_Sym* symtab; 121 122 size_t nbucket; 123 size_t nchain; 124 unsigned* bucket; 125 unsigned* chain; 126 127 unsigned* plt_got; 128 129 Elf32_Rel* plt_rel; 130 size_t plt_rel_count; 131 132 Elf32_Rel* rel; 133 size_t rel_count; 134 135 linker_function_t* preinit_array; 136 size_t preinit_array_count; 137 138 linker_function_t* init_array; 139 size_t init_array_count; 140 linker_function_t* fini_array; 141 size_t fini_array_count; 142 143 linker_function_t init_func; 144 linker_function_t fini_func; 145 146 #if defined(ANDROID_ARM_LINKER) 147 // ARM EABI section used for stack unwinding. 148 unsigned* ARM_exidx; 149 size_t ARM_exidx_count; 150 #elif defined(ANDROID_MIPS_LINKER) 151 unsigned mips_symtabno; 152 unsigned mips_local_gotno; 153 unsigned mips_gotsym; 154 #endif 155 156 size_t ref_count; 157 link_map_t link_map; 158 159 bool constructors_called; 160 161 // When you read a virtual address from the ELF file, add this 162 // value to get the corresponding address in the process' address space. 163 Elf32_Addr load_bias; 164 165 bool has_text_relocations; 166 bool has_DT_SYMBOLIC; 167 168 void CallConstructors(); 169 void CallDestructors(); 170 void CallPreInitConstructors(); 171 172 private: 173 void CallArray(const char* array_name, linker_function_t* functions, size_t count, bool reverse); 174 void CallFunction(const char* function_name, linker_function_t function); 175 }; 176 177 extern soinfo libdl_info; 178 179 // These aren't defined in <sys/exec_elf.h>. 180 #ifndef DT_PREINIT_ARRAY 181 #define DT_PREINIT_ARRAY 32 182 #endif 183 #ifndef DT_PREINIT_ARRAYSZ 184 #define DT_PREINIT_ARRAYSZ 33 185 #endif 186 187 void do_android_update_LD_LIBRARY_PATH(const char* ld_library_path); 188 soinfo* do_dlopen(const char* name, int flags); 189 int do_dlclose(soinfo* si); 190 191 Elf32_Sym* dlsym_linear_lookup(const char* name, soinfo** found, soinfo* start); 192 soinfo* find_containing_library(const void* addr); 193 194 Elf32_Sym* dladdr_find_symbol(soinfo* si, const void* addr); 195 Elf32_Sym* dlsym_handle_lookup(soinfo* si, const char* name); 196 197 void debuggerd_init(); 198 extern "C" abort_msg_t* gAbortMessage; 199 extern "C" void notify_gdb_of_libraries(); 200 201 char* linker_get_error_buffer(); 202 size_t linker_get_error_buffer_size(); 203 204 #endif 205