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 #ifdef __cplusplus 38 extern "C" { 39 #endif 40 #include <link.h> 41 42 #undef PAGE_MASK 43 #undef PAGE_SIZE 44 #define PAGE_SIZE 4096 45 #define PAGE_MASK (PAGE_SIZE-1) 46 47 /* Convenience macros to make page address/offset computations more explicit */ 48 49 /* Returns the address of the page starting at address 'x' */ 50 #define PAGE_START(x) ((x) & ~PAGE_MASK) 51 52 /* Returns the offset of address 'x' in its memory page, i.e. this is the 53 * same than 'x' - PAGE_START(x) */ 54 #define PAGE_OFFSET(x) ((x) & PAGE_MASK) 55 56 /* Returns the address of the next page after address 'x', unless 'x' is 57 * itself at the start of a page. Equivalent to: 58 * 59 * (x == PAGE_START(x)) ? x : PAGE_START(x)+PAGE_SIZE 60 */ 61 #define PAGE_END(x) PAGE_START((x) + (PAGE_SIZE-1)) 62 63 void debugger_init(); 64 65 /* magic shared structures that GDB knows about */ 66 67 struct link_map 68 { 69 uintptr_t l_addr; 70 char * l_name; 71 uintptr_t l_ld; 72 struct link_map * l_next; 73 struct link_map * l_prev; 74 }; 75 76 // Values for r_debug->state 77 enum { 78 RT_CONSISTENT, 79 RT_ADD, 80 RT_DELETE 81 }; 82 83 struct r_debug 84 { 85 int32_t r_version; 86 struct link_map * r_map; 87 void (*r_brk)(void); 88 int32_t r_state; 89 uintptr_t r_ldbase; 90 }; 91 92 typedef struct soinfo soinfo; 93 94 #define FLAG_LINKED 0x00000001 95 #define FLAG_ERROR 0x00000002 96 #define FLAG_EXE 0x00000004 // The main executable 97 #define FLAG_LINKER 0x00000010 // The linker itself 98 99 #define SOINFO_NAME_LEN 128 100 101 struct soinfo 102 { 103 char name[SOINFO_NAME_LEN]; 104 const Elf32_Phdr *phdr; 105 int phnum; 106 unsigned entry; 107 unsigned base; 108 unsigned size; 109 110 int unused; // DO NOT USE, maintained for compatibility. 111 112 unsigned *dynamic; 113 114 unsigned unused2; // DO NOT USE, maintained for compatibility 115 unsigned unused3; // DO NOT USE, maintained for compatibility 116 117 soinfo *next; 118 unsigned flags; 119 120 const char *strtab; 121 Elf32_Sym *symtab; 122 123 unsigned nbucket; 124 unsigned nchain; 125 unsigned *bucket; 126 unsigned *chain; 127 128 unsigned *plt_got; 129 130 Elf32_Rel *plt_rel; 131 unsigned plt_rel_count; 132 133 Elf32_Rel *rel; 134 unsigned rel_count; 135 136 unsigned *preinit_array; 137 unsigned preinit_array_count; 138 139 unsigned *init_array; 140 unsigned init_array_count; 141 unsigned *fini_array; 142 unsigned fini_array_count; 143 144 void (*init_func)(void); 145 void (*fini_func)(void); 146 147 #if defined(ANDROID_ARM_LINKER) 148 /* ARM EABI section used for stack unwinding. */ 149 unsigned *ARM_exidx; 150 unsigned ARM_exidx_count; 151 #elif defined(ANDROID_MIPS_LINKER) 152 #if 0 153 /* not yet */ 154 unsigned *mips_pltgot 155 #endif 156 unsigned mips_symtabno; 157 unsigned mips_local_gotno; 158 unsigned mips_gotsym; 159 #endif /* ANDROID_*_LINKER */ 160 161 unsigned refcount; 162 struct link_map linkmap; 163 164 int constructors_called; 165 166 /* When you read a virtual address from the ELF file, add this 167 * value to get the corresponding address in the process' address space */ 168 Elf32_Addr load_bias; 169 int has_text_relocations; 170 }; 171 172 173 extern soinfo libdl_info; 174 175 176 #include <asm/elf.h> 177 178 #if defined(ANDROID_ARM_LINKER) 179 180 // These aren't defined in <arch-arm/asm/elf.h>. 181 #define R_ARM_REL32 3 182 #define R_ARM_COPY 20 183 #define R_ARM_GLOB_DAT 21 184 #define R_ARM_JUMP_SLOT 22 185 #define R_ARM_RELATIVE 23 186 187 #elif defined(ANDROID_MIPS_LINKER) 188 189 // These aren't defined in <arch-arm/mips/elf.h>. 190 #define R_MIPS_JUMP_SLOT 127 191 192 #define DT_MIPS_PLTGOT 0x70000032 193 #define DT_MIPS_RWPLT 0x70000034 194 195 #elif defined(ANDROID_X86_LINKER) 196 197 // x86 has everything it needs in <arch-arm/x86/elf.h>. 198 199 #endif /* ANDROID_*_LINKER */ 200 201 #ifndef DT_INIT_ARRAY 202 #define DT_INIT_ARRAY 25 203 #endif 204 205 #ifndef DT_FINI_ARRAY 206 #define DT_FINI_ARRAY 26 207 #endif 208 209 #ifndef DT_INIT_ARRAYSZ 210 #define DT_INIT_ARRAYSZ 27 211 #endif 212 213 #ifndef DT_FINI_ARRAYSZ 214 #define DT_FINI_ARRAYSZ 28 215 #endif 216 217 #ifndef DT_PREINIT_ARRAY 218 #define DT_PREINIT_ARRAY 32 219 #endif 220 221 #ifndef DT_PREINIT_ARRAYSZ 222 #define DT_PREINIT_ARRAYSZ 33 223 #endif 224 225 soinfo *find_library(const char *name); 226 Elf32_Sym *lookup(const char *name, soinfo **found, soinfo *start); 227 soinfo *find_containing_library(const void *addr); 228 const char *linker_get_error(void); 229 230 int soinfo_unload(soinfo* si); 231 Elf32_Sym *soinfo_find_symbol(soinfo* si, const void *addr); 232 Elf32_Sym *soinfo_lookup(soinfo *si, const char *name); 233 void soinfo_call_constructors(soinfo *si); 234 235 #ifdef __cplusplus 236 }; 237 #endif 238 239 #endif 240