/* * 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_ #include #include #include #include #include "private/libc_logging.h" #define DL_ERR(fmt, x...) \ do { \ __libc_format_buffer(linker_get_error_buffer(), linker_get_error_buffer_size(), fmt, ##x); \ /* If LD_DEBUG is set high enough, log every dlerror(3) message. */ \ DEBUG("%s\n", linker_get_error_buffer()); \ } while (false) #define DL_WARN(fmt, x...) \ do { \ __libc_format_log(ANDROID_LOG_WARN, "linker", fmt, ##x); \ __libc_format_fd(2, "WARNING: linker: "); \ __libc_format_fd(2, fmt, ##x); \ __libc_format_fd(2, "\n"); \ } while (false) #if defined(__LP64__) #define ELFW(what) ELF64_ ## what #else #define ELFW(what) ELF32_ ## what #endif // mips64 interprets Elf64_Rel structures' r_info field differently. // bionic (like other C libraries) has macros that assume regular ELF files, // but the dynamic linker needs to be able to load mips64 ELF files. #if defined(__mips__) && defined(__LP64__) #undef ELF64_R_SYM #undef ELF64_R_TYPE #undef ELF64_R_INFO #define ELF64_R_SYM(info) (((info) >> 0) & 0xffffffff) #define ELF64_R_SSYM(info) (((info) >> 32) & 0xff) #define ELF64_R_TYPE3(info) (((info) >> 40) & 0xff) #define ELF64_R_TYPE2(info) (((info) >> 48) & 0xff) #define ELF64_R_TYPE(info) (((info) >> 56) & 0xff) #endif // 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)) #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 RELA for aarch64 and x86_64. mips64 still uses REL. #if defined(__aarch64__) || defined(__x86_64__) #define USE_RELA 1 #endif struct soinfo { public: char name[SOINFO_NAME_LEN]; const ElfW(Phdr)* phdr; size_t phnum; ElfW(Addr) entry; ElfW(Addr) base; size_t size; #ifndef __LP64__ uint32_t unused1; // DO NOT USE, maintained for compatibility. #endif ElfW(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; ElfW(Sym)* symtab; size_t nbucket; size_t nchain; unsigned* bucket; unsigned* chain; #if defined(__mips__) || !defined(__LP64__) // This is only used by mips and mips64, but needs to be here for // all 32-bit architectures to preserve binary compatibility. ElfW(Addr)** plt_got; #endif #if defined(USE_RELA) ElfW(Rela)* plt_rela; size_t plt_rela_count; ElfW(Rela)* rela; size_t rela_count; #else ElfW(Rel)* plt_rel; size_t plt_rel_count; ElfW(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 link_map_head; 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. ElfW(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); }; extern soinfo libdl_info; void do_android_get_LD_LIBRARY_PATH(char*, size_t); void do_android_update_LD_LIBRARY_PATH(const char* ld_library_path); soinfo* do_dlopen(const char* name, int flags, const android_dlextinfo* extinfo); int do_dlclose(soinfo* si); ElfW(Sym)* dlsym_linear_lookup(const char* name, soinfo** found, soinfo* start); soinfo* find_containing_library(const void* addr); ElfW(Sym)* dladdr_find_symbol(soinfo* si, const void* addr); ElfW(Sym)* dlsym_handle_lookup(soinfo* si, const char* name); void debuggerd_init(); extern "C" abort_msg_t* g_abort_message; extern "C" void notify_gdb_of_libraries(); char* linker_get_error_buffer(); size_t linker_get_error_buffer_size(); #endif