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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 <vector>
26 
27 #include <unwindstack/DwarfSection.h>
28 #include <unwindstack/Error.h>
29 #include <unwindstack/SharedString.h>
30 
31 namespace unwindstack {
32 
33 // Forward declarations.
34 class Memory;
35 class Regs;
36 class Symbols;
37 
38 struct LoadInfo {
39   uint64_t offset;
40   uint64_t table_offset;
41   size_t table_size;
42 };
43 
44 enum : uint8_t {
45   SONAME_UNKNOWN = 0,
46   SONAME_VALID,
47   SONAME_INVALID,
48 };
49 
50 struct ElfTypes32 {
51   using AddressType = uint32_t;
52   using Dyn = Elf32_Dyn;
53   using Ehdr = Elf32_Ehdr;
54   using Nhdr = Elf32_Nhdr;
55   using Phdr = Elf32_Phdr;
56   using Shdr = Elf32_Shdr;
57   using Sym = Elf32_Sym;
58 };
59 
60 struct ElfTypes64 {
61   using AddressType = uint64_t;
62   using Dyn = Elf64_Dyn;
63   using Ehdr = Elf64_Ehdr;
64   using Nhdr = Elf64_Nhdr;
65   using Phdr = Elf64_Phdr;
66   using Shdr = Elf64_Shdr;
67   using Sym = Elf64_Sym;
68 };
69 
70 class ElfInterface {
71  public:
ElfInterface(Memory * memory)72   ElfInterface(Memory* memory) : memory_(memory) {}
73   virtual ~ElfInterface();
74 
75   virtual bool Init(int64_t* load_bias) = 0;
76 
77   virtual void InitHeaders() = 0;
78 
79   virtual std::string GetSoname() = 0;
80 
81   virtual bool GetFunctionName(uint64_t addr, SharedString* name, uint64_t* offset) = 0;
82 
83   virtual bool GetGlobalVariable(const std::string& name, uint64_t* memory_address) = 0;
84 
85   virtual std::string GetBuildID() = 0;
86 
87   virtual bool Step(uint64_t rel_pc, Regs* regs, Memory* process_memory, bool* finished,
88                     bool* is_signal_frame);
89 
90   virtual bool IsValidPc(uint64_t pc);
91 
92   bool GetTextRange(uint64_t* addr, uint64_t* size);
93 
94   std::unique_ptr<Memory> CreateGnuDebugdataMemory();
95 
memory()96   Memory* memory() { return memory_; }
97 
pt_loads()98   const std::unordered_map<uint64_t, LoadInfo>& pt_loads() { return pt_loads_; }
99 
SetGnuDebugdataInterface(ElfInterface * interface)100   void SetGnuDebugdataInterface(ElfInterface* interface) { gnu_debugdata_interface_ = interface; }
101 
dynamic_offset()102   uint64_t dynamic_offset() { return dynamic_offset_; }
dynamic_vaddr_start()103   uint64_t dynamic_vaddr_start() { return dynamic_vaddr_start_; }
dynamic_vaddr_end()104   uint64_t dynamic_vaddr_end() { return dynamic_vaddr_end_; }
data_offset()105   uint64_t data_offset() { return data_offset_; }
data_vaddr_start()106   uint64_t data_vaddr_start() { return data_vaddr_start_; }
data_vaddr_end()107   uint64_t data_vaddr_end() { return data_vaddr_end_; }
eh_frame_hdr_offset()108   uint64_t eh_frame_hdr_offset() { return eh_frame_hdr_offset_; }
eh_frame_hdr_section_bias()109   int64_t eh_frame_hdr_section_bias() { return eh_frame_hdr_section_bias_; }
eh_frame_hdr_size()110   uint64_t eh_frame_hdr_size() { return eh_frame_hdr_size_; }
eh_frame_offset()111   uint64_t eh_frame_offset() { return eh_frame_offset_; }
eh_frame_section_bias()112   int64_t eh_frame_section_bias() { return eh_frame_section_bias_; }
eh_frame_size()113   uint64_t eh_frame_size() { return eh_frame_size_; }
debug_frame_offset()114   uint64_t debug_frame_offset() { return debug_frame_offset_; }
debug_frame_section_bias()115   int64_t debug_frame_section_bias() { return debug_frame_section_bias_; }
debug_frame_size()116   uint64_t debug_frame_size() { return debug_frame_size_; }
gnu_debugdata_offset()117   uint64_t gnu_debugdata_offset() { return gnu_debugdata_offset_; }
gnu_debugdata_size()118   uint64_t gnu_debugdata_size() { return gnu_debugdata_size_; }
gnu_build_id_offset()119   uint64_t gnu_build_id_offset() { return gnu_build_id_offset_; }
gnu_build_id_size()120   uint64_t gnu_build_id_size() { return gnu_build_id_size_; }
121 
eh_frame()122   DwarfSection* eh_frame() { return eh_frame_.get(); }
debug_frame()123   DwarfSection* debug_frame() { return debug_frame_.get(); }
124 
last_error()125   const ErrorData& last_error() { return last_error_; }
LastErrorCode()126   ErrorCode LastErrorCode() { return last_error_.code; }
LastErrorAddress()127   uint64_t LastErrorAddress() { return last_error_.address; }
128 
129   template <typename EhdrType, typename PhdrType>
130   static int64_t GetLoadBias(Memory* memory);
131 
132   template <typename EhdrType, typename ShdrType, typename NhdrType>
133   static std::string ReadBuildIDFromMemory(Memory* memory);
134 
135  protected:
HandleUnknownType(uint32_t,uint64_t,uint64_t)136   virtual void HandleUnknownType(uint32_t, uint64_t, uint64_t) {}
137 
138   Memory* memory_;
139   std::unordered_map<uint64_t, LoadInfo> pt_loads_;
140 
141   // Stored elf data.
142   uint64_t dynamic_offset_ = 0;
143   uint64_t dynamic_vaddr_start_ = 0;
144   uint64_t dynamic_vaddr_end_ = 0;
145 
146   uint64_t data_offset_ = 0;
147   uint64_t data_vaddr_start_ = 0;
148   uint64_t data_vaddr_end_ = 0;
149 
150   uint64_t eh_frame_hdr_offset_ = 0;
151   int64_t eh_frame_hdr_section_bias_ = 0;
152   uint64_t eh_frame_hdr_size_ = 0;
153 
154   uint64_t eh_frame_offset_ = 0;
155   int64_t eh_frame_section_bias_ = 0;
156   uint64_t eh_frame_size_ = 0;
157 
158   uint64_t debug_frame_offset_ = 0;
159   int64_t debug_frame_section_bias_ = 0;
160   uint64_t debug_frame_size_ = 0;
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 DynType = typename ElfTypes::Dyn;
190   using EhdrType = typename ElfTypes::Ehdr;
191   using NhdrType = typename ElfTypes::Nhdr;
192   using PhdrType = typename ElfTypes::Phdr;
193   using ShdrType = typename ElfTypes::Shdr;
194   using SymType = typename ElfTypes::Sym;
195 
ElfInterfaceImpl(Memory * memory)196   ElfInterfaceImpl(Memory* memory) : ElfInterface(memory) {}
197   virtual ~ElfInterfaceImpl() = default;
198 
Init(int64_t * load_bias)199   bool Init(int64_t* load_bias) override { return ReadAllHeaders(load_bias); }
200 
201   void InitHeaders() override;
202 
203   std::string GetSoname() override;
204 
205   bool GetFunctionName(uint64_t addr, SharedString* name, uint64_t* func_offset) override;
206 
207   bool GetGlobalVariable(const std::string& name, uint64_t* memory_address) override;
208 
GetBuildID()209   std::string GetBuildID() override { return ReadBuildID(); }
210 
211   static void GetMaxSize(Memory* memory, uint64_t* size);
212 
213  protected:
214   bool ReadAllHeaders(int64_t* load_bias);
215 
216   void ReadProgramHeaders(const EhdrType& ehdr, int64_t* load_bias);
217 
218   void ReadSectionHeaders(const EhdrType& ehdr);
219 
220   std::string ReadBuildID();
221 };
222 
223 using ElfInterface32 = ElfInterfaceImpl<ElfTypes32>;
224 using ElfInterface64 = ElfInterfaceImpl<ElfTypes64>;
225 
226 }  // namespace unwindstack
227