/* * Copyright (C) 2008 The Android Open Source Project * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #ifndef _LINKER_H_ #define _LINKER_H_ #ifdef __ANDROID__ #include <unistd.h> #include <sys/types.h> // #include <elf.h> #include <linux/elf.h> // #include <sys/exec_elf.h> // #include <link.h> // a1ba: we don't really need custom linker on Android 64, because // it's only intended to workaround bug which persist on Android < 4.4 #define Elf_Ehdr Elf32_Ehdr #define Elf_Phdr Elf32_Phdr #define Elf_Shdr Elf32_Shdr #define Elf_Sym Elf32_Sym #define Elf_Rel Elf32_Rel #define Elf_RelA Elf32_Rela #define Elf_Dyn Elf32_Dyn #define Elf_Half Elf32_Half #define Elf_Word Elf32_Word #define Elf_Sword Elf32_Sword #define Elf_Addr Elf32_Addr #define Elf_Off Elf32_Off #define Elf_Nhdr Elf32_Nhdr #define Elf_Note Elf32_Note // Returns the address of the page containing address 'x'. #define PAGE_START(x) ((x) & PAGE_MASK) // Returns the offset of address 'x' in its page. #define PAGE_OFFSET(x) ((x) & ~PAGE_MASK) // Returns the address of the next page after address 'x', unless 'x' is // itself at the start of a page. #define PAGE_END(x) PAGE_START((x) + (PAGE_SIZE-1)) // Magic shared structures that GDB knows about. struct link_map_t { uintptr_t l_addr; char* l_name; uintptr_t l_ld; link_map_t* l_next; link_map_t* l_prev; }; // Values for r_debug->state enum { RT_CONSISTENT, RT_ADD, RT_DELETE }; #if 0 struct r_debug { int32_t r_version; link_map_t* r_map; void (*r_brk)(void); int32_t r_state; uintptr_t r_ldbase; }; #endif #define FLAG_LINKED 0x00000001 #define FLAG_EXE 0x00000004 // The main executable #define FLAG_LINKER 0x00000010 // The linker itself #define SOINFO_NAME_LEN 128 typedef void (*linker_function_t)(); // Android uses REL for 32-bit but only uses RELA for 64-bit. #if defined(__LP64__) #define USE_RELA 1 #endif struct soinfo { public: char name[SOINFO_NAME_LEN]; const Elf_Phdr* phdr; size_t phnum; Elf_Addr entry; Elf_Addr base; unsigned size; #ifndef __LP64__ uint32_t unused1; // DO NOT USE, maintained for compatibility. #endif Elf_Dyn* dynamic; #ifndef __LP64__ uint32_t unused2; // DO NOT USE, maintained for compatibility uint32_t unused3; // DO NOT USE, maintained for compatibility #endif soinfo* next; unsigned flags; const char* strtab; Elf_Sym* symtab; size_t nbucket; size_t nchain; unsigned* bucket; unsigned* chain; #if !defined(__LP64__) // This is only used by 32-bit MIPS, but needs to be here for // all 32-bit architectures to preserve binary compatibility. unsigned* plt_got; #endif #if defined(USE_RELA) Elf_Rela* plt_rela; size_t plt_rela_count; Elf_Rela* rela; size_t rela_count; #else Elf_Rel* plt_rel; size_t plt_rel_count; Elf_Rel* rel; size_t rel_count; #endif linker_function_t* preinit_array; size_t preinit_array_count; linker_function_t* init_array; size_t init_array_count; linker_function_t* fini_array; size_t fini_array_count; linker_function_t init_func; linker_function_t fini_func; #if defined(__arm__) // ARM EABI section used for stack unwinding. unsigned* ARM_exidx; size_t ARM_exidx_count; #elif defined(__mips__) unsigned mips_symtabno; unsigned mips_local_gotno; unsigned mips_gotsym; #endif size_t ref_count; link_map_t link_map; bool constructors_called; // When you read a virtual address from the ELF file, add this // value to get the corresponding address in the process' address space. Elf_Addr load_bias; #if !defined(__LP64__) bool has_text_relocations; #endif bool has_DT_SYMBOLIC; void CallConstructors(); void CallDestructors(); void CallPreInitConstructors(); private: void CallArray(const char* array_name, linker_function_t* functions, size_t count, bool reverse); void CallFunction(const char* function_name, linker_function_t function); }; #endif #endif