250 lines
7 KiB
C++
250 lines
7 KiB
C++
/*
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* Copyright (C) 2008 The Android Open Source Project
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#ifndef _LINKER_H_
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#define _LINKER_H_
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#include <elf.h>
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#include <link.h>
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#include <unistd.h>
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#include <android/dlext.h>
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#include <sys/stat.h>
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#include "private/libc_logging.h"
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#include "linked_list.h"
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#define DL_ERR(fmt, x...) \
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do { \
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__libc_format_buffer(linker_get_error_buffer(), linker_get_error_buffer_size(), fmt, ##x); \
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/* If LD_DEBUG is set high enough, log every dlerror(3) message. */ \
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DEBUG("%s\n", linker_get_error_buffer()); \
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} while (false)
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#define DL_WARN(fmt, x...) \
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do { \
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__libc_format_log(ANDROID_LOG_WARN, "linker", fmt, ##x); \
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__libc_format_fd(2, "WARNING: linker: "); \
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__libc_format_fd(2, fmt, ##x); \
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__libc_format_fd(2, "\n"); \
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} while (false)
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#if defined(__LP64__)
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#define ELFW(what) ELF64_ ## what
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#else
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#define ELFW(what) ELF32_ ## what
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#endif
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// mips64 interprets Elf64_Rel structures' r_info field differently.
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// bionic (like other C libraries) has macros that assume regular ELF files,
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// but the dynamic linker needs to be able to load mips64 ELF files.
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#if defined(__mips__) && defined(__LP64__)
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#undef ELF64_R_SYM
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#undef ELF64_R_TYPE
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#undef ELF64_R_INFO
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#define ELF64_R_SYM(info) (((info) >> 0) & 0xffffffff)
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#define ELF64_R_SSYM(info) (((info) >> 32) & 0xff)
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#define ELF64_R_TYPE3(info) (((info) >> 40) & 0xff)
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#define ELF64_R_TYPE2(info) (((info) >> 48) & 0xff)
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#define ELF64_R_TYPE(info) (((info) >> 56) & 0xff)
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#endif
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// Returns the address of the page containing address 'x'.
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#define PAGE_START(x) ((x) & PAGE_MASK)
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// Returns the offset of address 'x' in its page.
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#define PAGE_OFFSET(x) ((x) & ~PAGE_MASK)
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// Returns the address of the next page after address 'x', unless 'x' is
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// itself at the start of a page.
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#define PAGE_END(x) PAGE_START((x) + (PAGE_SIZE-1))
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#define FLAG_LINKED 0x00000001
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#define FLAG_EXE 0x00000004 // The main executable
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#define FLAG_LINKER 0x00000010 // The linker itself
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#define FLAG_NEW_SOINFO 0x40000000 // new soinfo format
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#define SOINFO_NAME_LEN 128
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typedef void (*linker_function_t)();
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// Android uses RELA for aarch64 and x86_64. mips64 still uses REL.
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#if defined(__aarch64__) || defined(__x86_64__)
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#define USE_RELA 1
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#endif
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struct soinfo;
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class SoinfoListAllocator {
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public:
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static LinkedListEntry<soinfo>* alloc();
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static void free(LinkedListEntry<soinfo>* entry);
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private:
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// unconstructable
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DISALLOW_IMPLICIT_CONSTRUCTORS(SoinfoListAllocator);
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};
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struct soinfo {
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public:
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typedef LinkedList<soinfo, SoinfoListAllocator> soinfo_list_t;
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public:
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char name[SOINFO_NAME_LEN];
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const ElfW(Phdr)* phdr;
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size_t phnum;
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ElfW(Addr) entry;
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ElfW(Addr) base;
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size_t size;
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#ifndef __LP64__
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uint32_t unused1; // DO NOT USE, maintained for compatibility.
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#endif
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ElfW(Dyn)* dynamic;
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#ifndef __LP64__
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uint32_t unused2; // DO NOT USE, maintained for compatibility
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uint32_t unused3; // DO NOT USE, maintained for compatibility
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#endif
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soinfo* next;
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unsigned flags;
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const char* strtab;
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ElfW(Sym)* symtab;
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size_t nbucket;
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size_t nchain;
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unsigned* bucket;
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unsigned* chain;
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#if defined(__mips__) || !defined(__LP64__)
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// This is only used by mips and mips64, but needs to be here for
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// all 32-bit architectures to preserve binary compatibility.
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ElfW(Addr)** plt_got;
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#endif
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#if defined(USE_RELA)
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ElfW(Rela)* plt_rela;
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size_t plt_rela_count;
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ElfW(Rela)* rela;
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size_t rela_count;
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#else
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ElfW(Rel)* plt_rel;
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size_t plt_rel_count;
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ElfW(Rel)* rel;
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size_t rel_count;
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#endif
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linker_function_t* preinit_array;
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size_t preinit_array_count;
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linker_function_t* init_array;
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size_t init_array_count;
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linker_function_t* fini_array;
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size_t fini_array_count;
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linker_function_t init_func;
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linker_function_t fini_func;
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#if defined(__arm__)
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// ARM EABI section used for stack unwinding.
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unsigned* ARM_exidx;
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size_t ARM_exidx_count;
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#elif defined(__mips__)
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unsigned mips_symtabno;
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unsigned mips_local_gotno;
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unsigned mips_gotsym;
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#endif
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size_t ref_count;
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link_map link_map_head;
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bool constructors_called;
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// When you read a virtual address from the ELF file, add this
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// value to get the corresponding address in the process' address space.
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ElfW(Addr) load_bias;
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#if !defined(__LP64__)
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bool has_text_relocations;
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#endif
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bool has_DT_SYMBOLIC;
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void CallConstructors();
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void CallDestructors();
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void CallPreInitConstructors();
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void add_child(soinfo* child);
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void remove_all_links();
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void set_st_dev(dev_t st_dev);
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void set_st_ino(ino_t st_ino);
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ino_t get_st_ino();
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dev_t get_st_dev();
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soinfo_list_t& get_children();
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private:
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void CallArray(const char* array_name, linker_function_t* functions, size_t count, bool reverse);
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void CallFunction(const char* function_name, linker_function_t function);
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private:
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// This part of the structure is only available
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// when FLAG_NEW_SOINFO is set in this->flags.
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unsigned int version;
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dev_t st_dev;
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ino_t st_ino;
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// dependency graph
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soinfo_list_t children;
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soinfo_list_t parents;
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};
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extern soinfo* get_libdl_info();
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void do_android_get_LD_LIBRARY_PATH(char*, size_t);
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void do_android_update_LD_LIBRARY_PATH(const char* ld_library_path);
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soinfo* do_dlopen(const char* name, int flags, const android_dlextinfo* extinfo);
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void do_dlclose(soinfo* si);
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ElfW(Sym)* dlsym_linear_lookup(const char* name, soinfo** found, soinfo* start);
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soinfo* find_containing_library(const void* addr);
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ElfW(Sym)* dladdr_find_symbol(soinfo* si, const void* addr);
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ElfW(Sym)* dlsym_handle_lookup(soinfo* si, const char* name);
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void debuggerd_init();
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extern "C" abort_msg_t* g_abort_message;
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extern "C" void notify_gdb_of_libraries();
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char* linker_get_error_buffer();
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size_t linker_get_error_buffer_size();
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#endif
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