/*
* Copyright (C) 2016 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.
*/
#pragma once
#include <link.h>
#include <string>
#include "linker_namespaces.h"
#define FLAG_LINKED 0x00000001
#define FLAG_EXE 0x00000004 // The main executable
#define FLAG_LINKER 0x00000010 // The linker itself
#define FLAG_GNU_HASH 0x00000040 // uses gnu hash
#define FLAG_MAPPED_BY_CALLER 0x00000080 // the map is reserved by the caller
// and should not be unmapped
#define FLAG_IMAGE_LINKED 0x00000100 // Is image linked - this is a guard on link_image.
// The difference between this flag and
// FLAG_LINKED is that FLAG_LINKED
// means is set when load_group is
// successfully loaded whereas this
// flag is set to avoid linking image
// when link_image called for the
// second time. This situation happens
// when load group is crossing
// namespace boundary twice and second
// local group depends on the same libraries.
#define FLAG_TLS_NODELETE 0x00000200 // This flag set when there is at least one
// outstanding thread_local dtor
// registered with this soinfo. In such
// a case the actual unload is
// postponed until the last thread_local
// destructor associated with this
// soinfo is executed and this flag is
// unset.
#define FLAG_NEW_SOINFO 0x40000000 // new soinfo format
#define SOINFO_VERSION 4
typedef void (*linker_dtor_function_t)();
typedef void (*linker_ctor_function_t)(int, char**, char**);
class SymbolName {
public:
explicit SymbolName(const char* name)
: name_(name), has_elf_hash_(false), has_gnu_hash_(false),
elf_hash_(0), gnu_hash_(0) { }
const char* get_name() {
return name_;
}
uint32_t elf_hash();
uint32_t gnu_hash();
private:
const char* name_;
bool has_elf_hash_;
bool has_gnu_hash_;
uint32_t elf_hash_;
uint32_t gnu_hash_;
DISALLOW_IMPLICIT_CONSTRUCTORS(SymbolName);
};
struct version_info {
constexpr version_info() : elf_hash(0), name(nullptr), target_si(nullptr) {}
uint32_t elf_hash;
const char* name;
const soinfo* target_si;
};
// TODO(dimitry): remove reference from soinfo member functions to this class.
class VersionTracker;
#if defined(__work_around_b_24465209__)
#define SOINFO_NAME_LEN 128
#endif
struct soinfo {
#if defined(__work_around_b_24465209__)
private:
char old_name_[SOINFO_NAME_LEN];
#endif
public:
const ElfW(Phdr)* phdr;
size_t phnum;
#if defined(__work_around_b_24465209__)
ElfW(Addr) unused0; // DO NOT USE, maintained for compatibility.
#endif
ElfW(Addr) base;
size_t size;
#if defined(__work_around_b_24465209__)
uint32_t unused1; // DO NOT USE, maintained for compatibility.
#endif
ElfW(Dyn)* dynamic;
#if defined(__work_around_b_24465209__)
uint32_t unused2; // DO NOT USE, maintained for compatibility
uint32_t unused3; // DO NOT USE, maintained for compatibility
#endif
soinfo* next;
private:
uint32_t flags_;
const char* strtab_;
ElfW(Sym)* symtab_;
size_t nbucket_;
size_t nchain_;
uint32_t* bucket_;
uint32_t* 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_ctor_function_t* preinit_array_;
size_t preinit_array_count_;
linker_ctor_function_t* init_array_;
size_t init_array_count_;
linker_dtor_function_t* fini_array_;
size_t fini_array_count_;
linker_ctor_function_t init_func_;
linker_dtor_function_t fini_func_;
#if defined(__arm__)
public:
// ARM EABI section used for stack unwinding.
uint32_t* ARM_exidx;
size_t ARM_exidx_count;
private:
#elif defined(__mips__)
uint32_t mips_symtabno_;
uint32_t mips_local_gotno_;
uint32_t mips_gotsym_;
bool mips_relocate_got(const VersionTracker& version_tracker,
const soinfo_list_t& global_group,
const soinfo_list_t& local_group);
#if !defined(__LP64__)
bool mips_check_and_adjust_fp_modes();
#endif
#endif
size_t ref_count_;
public:
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;
public:
soinfo(android_namespace_t* ns, const char* name, const struct stat* file_stat,
off64_t file_offset, int rtld_flags);
~soinfo();
void call_constructors();
void call_destructors();
void call_pre_init_constructors();
bool prelink_image();
bool link_image(const soinfo_list_t& global_group, const soinfo_list_t& local_group,
const android_dlextinfo* extinfo);
bool protect_relro();
void add_child(soinfo* child);
void remove_all_links();
ino_t get_st_ino() const;
dev_t get_st_dev() const;
off64_t get_file_offset() const;
uint32_t get_rtld_flags() const;
uint32_t get_dt_flags_1() const;
void set_dt_flags_1(uint32_t dt_flags_1);
soinfo_list_t& get_children();
const soinfo_list_t& get_children() const;
soinfo_list_t& get_parents();
bool find_symbol_by_name(SymbolName& symbol_name,
const version_info* vi,
const ElfW(Sym)** symbol) const;
ElfW(Sym)* find_symbol_by_address(const void* addr);
ElfW(Addr) resolve_symbol_address(const ElfW(Sym)* s) const;
const char* get_string(ElfW(Word) index) const;
bool can_unload() const;
bool is_gnu_hash() const;
bool inline has_min_version(uint32_t min_version __unused) const {
#if defined(__work_around_b_24465209__)
return (flags_ & FLAG_NEW_SOINFO) != 0 && version_ >= min_version;
#else
return true;
#endif
}
bool is_linked() const;
bool is_linker() const;
bool is_main_executable() const;
void set_linked();
void set_linker_flag();
void set_main_executable();
void set_nodelete();
void set_tls_nodelete();
void unset_tls_nodelete();
size_t increment_ref_count();
size_t decrement_ref_count();
size_t get_ref_count() const;
soinfo* get_local_group_root() const;
void set_soname(const char* soname);
const char* get_soname() const;
const char* get_realpath() const;
const ElfW(Versym)* get_versym(size_t n) const;
ElfW(Addr) get_verneed_ptr() const;
size_t get_verneed_cnt() const;
ElfW(Addr) get_verdef_ptr() const;
size_t get_verdef_cnt() const;
uint32_t get_target_sdk_version() const;
void set_dt_runpath(const char *);
const std::vector<std::string>& get_dt_runpath() const;
android_namespace_t* get_primary_namespace();
void add_secondary_namespace(android_namespace_t* secondary_ns);
android_namespace_list_t& get_secondary_namespaces();
void set_mapped_by_caller(bool reserved_map);
bool is_mapped_by_caller() const;
uintptr_t get_handle() const;
void generate_handle();
void* to_handle();
private:
bool is_image_linked() const;
void set_image_linked();
bool elf_lookup(SymbolName& symbol_name, const version_info* vi, uint32_t* symbol_index) const;
ElfW(Sym)* elf_addr_lookup(const void* addr);
bool gnu_lookup(SymbolName& symbol_name, const version_info* vi, uint32_t* symbol_index) const;
ElfW(Sym)* gnu_addr_lookup(const void* addr);
bool lookup_version_info(const VersionTracker& version_tracker, ElfW(Word) sym,
const char* sym_name, const version_info** vi);
template<typename ElfRelIteratorT>
bool relocate(const VersionTracker& version_tracker, ElfRelIteratorT&& rel_iterator,
const soinfo_list_t& global_group, const soinfo_list_t& local_group);
bool relocate_relr();
void apply_relr_reloc(ElfW(Addr) offset);
private:
// This part of the structure is only available
// when FLAG_NEW_SOINFO is set in this->flags.
uint32_t version_;
// version >= 0
dev_t st_dev_;
ino_t st_ino_;
// dependency graph
soinfo_list_t children_;
soinfo_list_t parents_;
// version >= 1
off64_t file_offset_;
uint32_t rtld_flags_;
uint32_t dt_flags_1_;
size_t strtab_size_;
// version >= 2
size_t gnu_nbucket_;
uint32_t* gnu_bucket_;
uint32_t* gnu_chain_;
uint32_t gnu_maskwords_;
uint32_t gnu_shift2_;
ElfW(Addr)* gnu_bloom_filter_;
soinfo* local_group_root_;
uint8_t* android_relocs_;
size_t android_relocs_size_;
const char* soname_;
std::string realpath_;
const ElfW(Versym)* versym_;
ElfW(Addr) verdef_ptr_;
size_t verdef_cnt_;
ElfW(Addr) verneed_ptr_;
size_t verneed_cnt_;
uint32_t target_sdk_version_;
// version >= 3
std::vector<std::string> dt_runpath_;
android_namespace_t* primary_namespace_;
android_namespace_list_t secondary_namespaces_;
uintptr_t handle_;
friend soinfo* get_libdl_info(const char* linker_path,
const soinfo& linker_si,
const link_map& linker_map);
// version >= 4
ElfW(Relr)* relr_;
size_t relr_count_;
};
// This function is used by dlvsym() to calculate hash of sym_ver
uint32_t calculate_elf_hash(const char* name);
const char* fix_dt_needed(const char* dt_needed, const char* sopath);
template<typename F>
void for_each_dt_needed(const soinfo* si, F action) {
for (const ElfW(Dyn)* d = si->dynamic; d->d_tag != DT_NULL; ++d) {
if (d->d_tag == DT_NEEDED) {
action(fix_dt_needed(si->get_string(d->d_un.d_val), si->get_realpath()));
}
}
}