1 /*
2  * Copyright (C) 2016 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #pragma once
18 
19 #include <elf.h>
20 #include <stdint.h>
21 
22 #include <memory>
23 #include <string>
24 #include <unordered_map>
25 #include <utility>
26 #include <vector>
27 
28 #include <unwindstack/DwarfSection.h>
29 #include <unwindstack/Error.h>
30 #include <unwindstack/SharedString.h>
31 
32 namespace unwindstack {
33 
34 // Forward declarations.
35 class Memory;
36 class Regs;
37 class Symbols;
38 
39 struct LoadInfo {
40   uint64_t offset;
41   uint64_t table_offset;
42   size_t table_size;
43 };
44 
45 struct SectionInfo {
46   uint64_t offset;
47   uint64_t size;
48   uint64_t flags;
49   int64_t bias;
50 };
51 
52 enum : uint8_t {
53   SONAME_UNKNOWN = 0,
54   SONAME_VALID,
55   SONAME_INVALID,
56 };
57 
58 struct ElfTypes32 {
59   using AddressType = uint32_t;
60   using Chdr = Elf32_Chdr;
61   using Dyn = Elf32_Dyn;
62   using Ehdr = Elf32_Ehdr;
63   using Nhdr = Elf32_Nhdr;
64   using Phdr = Elf32_Phdr;
65   using Shdr = Elf32_Shdr;
66   using Sym = Elf32_Sym;
67 };
68 
69 struct ElfTypes64 {
70   using AddressType = uint64_t;
71   using Chdr = Elf64_Chdr;
72   using Dyn = Elf64_Dyn;
73   using Ehdr = Elf64_Ehdr;
74   using Nhdr = Elf64_Nhdr;
75   using Phdr = Elf64_Phdr;
76   using Shdr = Elf64_Shdr;
77   using Sym = Elf64_Sym;
78 };
79 
80 class ElfInterface {
81  public:
ElfInterface(std::shared_ptr<Memory> & memory)82   ElfInterface(std::shared_ptr<Memory>& memory) : memory_(memory) {}
83   virtual ~ElfInterface();
84 
85   virtual bool Init(int64_t* load_bias) = 0;
86 
87   virtual void InitHeaders() = 0;
88 
89   virtual std::string GetSoname() = 0;
90 
91   virtual bool GetFunctionName(uint64_t addr, SharedString* name, uint64_t* offset) = 0;
92 
93   virtual bool GetGlobalVariable(const std::string& name, uint64_t* memory_address) = 0;
94 
95   virtual std::string GetBuildID() = 0;
96 
97   virtual bool Step(uint64_t rel_pc, Regs* regs, Memory* process_memory, bool* finished,
98                     bool* is_signal_frame);
99 
100   virtual bool IsValidPc(uint64_t pc);
101 
102   bool GetTextRange(uint64_t* addr, uint64_t* size);
103 
104   std::shared_ptr<Memory> CreateGnuDebugdataMemory();
105 
memory()106   std::shared_ptr<Memory> memory() { return memory_; }
107 
pt_loads()108   const std::unordered_map<uint64_t, LoadInfo>& pt_loads() { return pt_loads_; }
109 
SetGnuDebugdataInterface(ElfInterface * interface)110   void SetGnuDebugdataInterface(ElfInterface* interface) { gnu_debugdata_interface_ = interface; }
111 
dynamic_offset()112   uint64_t dynamic_offset() { return dynamic_offset_; }
dynamic_vaddr_start()113   uint64_t dynamic_vaddr_start() { return dynamic_vaddr_start_; }
dynamic_vaddr_end()114   uint64_t dynamic_vaddr_end() { return dynamic_vaddr_end_; }
115 
data_offset()116   uint64_t data_offset() { return data_offset_; }
data_vaddr_start()117   uint64_t data_vaddr_start() { return data_vaddr_start_; }
data_vaddr_end()118   uint64_t data_vaddr_end() { return data_vaddr_end_; }
119 
eh_frame_hdr_info()120   const SectionInfo& eh_frame_hdr_info() { return eh_frame_hdr_info_; }
eh_frame_info()121   const SectionInfo& eh_frame_info() { return eh_frame_info_; }
debug_frame_info()122   const SectionInfo& debug_frame_info() { return debug_frame_info_; }
123 
gnu_debugdata_offset()124   uint64_t gnu_debugdata_offset() { return gnu_debugdata_offset_; }
gnu_debugdata_size()125   uint64_t gnu_debugdata_size() { return gnu_debugdata_size_; }
126 
gnu_build_id_offset()127   uint64_t gnu_build_id_offset() { return gnu_build_id_offset_; }
gnu_build_id_size()128   uint64_t gnu_build_id_size() { return gnu_build_id_size_; }
129 
eh_frame()130   DwarfSection* eh_frame() { return eh_frame_.get(); }
debug_frame()131   DwarfSection* debug_frame() { return debug_frame_.get(); }
132 
last_error()133   const ErrorData& last_error() { return last_error_; }
LastErrorCode()134   ErrorCode LastErrorCode() { return last_error_.code; }
LastErrorAddress()135   uint64_t LastErrorAddress() { return last_error_.address; }
136 
137   template <typename EhdrType, typename PhdrType>
138   static int64_t GetLoadBias(Memory* memory);
139 
140   template <typename EhdrType, typename ShdrType, typename NhdrType>
141   static std::string ReadBuildIDFromMemory(Memory* memory);
142 
143  protected:
HandleUnknownType(uint32_t,uint64_t,uint64_t)144   virtual void HandleUnknownType(uint32_t, uint64_t, uint64_t) {}
145 
146   std::shared_ptr<Memory> memory_;
147   std::unordered_map<uint64_t, LoadInfo> pt_loads_;
148 
149   // Stored elf data.
150   uint64_t dynamic_offset_ = 0;
151   uint64_t dynamic_vaddr_start_ = 0;
152   uint64_t dynamic_vaddr_end_ = 0;
153 
154   uint64_t data_offset_ = 0;
155   uint64_t data_vaddr_start_ = 0;
156   uint64_t data_vaddr_end_ = 0;
157 
158   SectionInfo eh_frame_hdr_info_ = {};
159   SectionInfo eh_frame_info_ = {};
160   SectionInfo debug_frame_info_ = {};
161 
162   uint64_t gnu_debugdata_offset_ = 0;
163   uint64_t gnu_debugdata_size_ = 0;
164 
165   uint64_t gnu_build_id_offset_ = 0;
166   uint64_t gnu_build_id_size_ = 0;
167 
168   uint64_t text_addr_ = 0;
169   uint64_t text_size_ = 0;
170 
171   uint8_t soname_type_ = SONAME_UNKNOWN;
172   std::string soname_;
173 
174   ErrorData last_error_{ERROR_NONE, 0};
175 
176   std::unique_ptr<DwarfSection> eh_frame_;
177   std::unique_ptr<DwarfSection> debug_frame_;
178   // The Elf object owns the gnu_debugdata interface object.
179   ElfInterface* gnu_debugdata_interface_ = nullptr;
180 
181   std::vector<Symbols*> symbols_;
182   std::vector<std::pair<uint64_t, uint64_t>> strtabs_;
183 };
184 
185 template <typename ElfTypes>
186 class ElfInterfaceImpl : public ElfInterface {
187  public:
188   using AddressType = typename ElfTypes::AddressType;
189   using ChdrType = typename ElfTypes::Chdr;
190   using DynType = typename ElfTypes::Dyn;
191   using EhdrType = typename ElfTypes::Ehdr;
192   using NhdrType = typename ElfTypes::Nhdr;
193   using PhdrType = typename ElfTypes::Phdr;
194   using ShdrType = typename ElfTypes::Shdr;
195   using SymType = typename ElfTypes::Sym;
196 
ElfInterfaceImpl(std::shared_ptr<Memory> & memory)197   ElfInterfaceImpl(std::shared_ptr<Memory>& memory) : ElfInterface(memory) {}
198   virtual ~ElfInterfaceImpl() = default;
199 
Init(int64_t * load_bias)200   bool Init(int64_t* load_bias) override { return ReadAllHeaders(load_bias); }
201 
202   void InitHeaders() override;
203 
204   std::string GetSoname() override;
205 
206   bool GetFunctionName(uint64_t addr, SharedString* name, uint64_t* func_offset) override;
207 
208   bool GetGlobalVariable(const std::string& name, uint64_t* memory_address) override;
209 
GetBuildID()210   std::string GetBuildID() override { return ReadBuildID(); }
211 
212   static void GetMaxSize(Memory* memory, uint64_t* size);
213 
214  protected:
215   bool ReadAllHeaders(int64_t* load_bias);
216 
217   void ReadProgramHeaders(const EhdrType& ehdr, int64_t* load_bias);
218 
219   void ReadSectionHeaders(const EhdrType& ehdr);
220 
221   std::string ReadBuildID();
222 };
223 
224 using ElfInterface32 = ElfInterfaceImpl<ElfTypes32>;
225 using ElfInterface64 = ElfInterfaceImpl<ElfTypes64>;
226 
227 }  // namespace unwindstack
228