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1 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
2 // -*- Mode: C++ -*-
3 //
4 // Copyright (C) 2020-2022 Google, Inc.
5 
6 /// @file
7 ///
8 /// This contains a set of ELF utilities used by the dwarf reader.
9 
10 #ifndef __ABG_ELF_HELPERS_H__
11 #define __ABG_ELF_HELPERS_H__
12 
13 #include "config.h"
14 
15 #include <elfutils/libdwfl.h>
16 #include <gelf.h>
17 #include <string>
18 
19 #include "abg-ir.h"
20 
21 namespace abigail
22 {
23 
24 namespace elf_helpers
25 {
26 
27 /// A functor used by @ref dwfl_sptr.
28 struct dwfl_deleter
29 {
30   void
operatordwfl_deleter31   operator()(Dwfl* dwfl)
32   {dwfl_end(dwfl);}
33 };//end struct dwfl_deleter
34 
35 /// A convenience typedef for a shared pointer to a Dwfl.
36 typedef shared_ptr<Dwfl> dwfl_sptr;
37 
38 /// Convenience typedef for a map which key is an elf address and
39 /// which value is an elf_symbol_sptr.
40 typedef unordered_map<GElf_Addr, elf_symbol_sptr> addr_elf_symbol_sptr_map_type;
41 
42 /// Convenience typedef for a set of ELF addresses.
43 typedef unordered_set<GElf_Addr> address_set_type;
44 
45 /// Convenience typedef for a shared pointer to an @ref address_set_type.
46 typedef shared_ptr<address_set_type> address_set_sptr;
47 
48 //
49 // ELF Value Converters
50 //
51 
52 elf_symbol::type
53 stt_to_elf_symbol_type(unsigned char stt);
54 
55 elf_symbol::binding
56 stb_to_elf_symbol_binding(unsigned char stb);
57 
58 elf_symbol::visibility
59 stv_to_elf_symbol_visibility(unsigned char stv);
60 
61 std::string
62 e_machine_to_string(GElf_Half e_machine);
63 
64 //
65 // ELF section helpers
66 //
67 
68 Elf_Scn*
69 find_section(Elf*		elf_handle,
70 	     const std::string& name,
71 	     Elf64_Word		section_type);
72 
73 Elf_Scn*
74 find_section_by_name(Elf* elf_handle, const std::string& name);
75 
76 Elf_Scn*
77 find_section(Elf* elf_handle, Elf64_Word section_type);
78 
79 Elf_Scn*
80 find_symtab_section(Elf* elf_handle);
81 
82 Elf_Scn*
83 find_dynsym_section(Elf* elf_handle);
84 
85 Elf_Scn*
86 find_symbol_table_section(Elf* elf_handle);
87 
88 bool
89 find_symbol_table_section_index(Elf* elf_handle, size_t& symtab_index);
90 
91 enum hash_table_kind
92 {
93   NO_HASH_TABLE_KIND = 0,
94   SYSV_HASH_TABLE_KIND,
95   GNU_HASH_TABLE_KIND
96 };
97 
98 hash_table_kind
99 find_hash_table_section_index(Elf*	elf_handle,
100 			      size_t&	ht_section_index,
101 			      size_t&	symtab_section_index);
102 
103 Elf_Scn*
104 find_text_section(Elf* elf_handle);
105 
106 Elf_Scn*
107 find_bss_section(Elf* elf_handle);
108 
109 Elf_Scn*
110 find_rodata_section(Elf* elf_handle);
111 
112 Elf_Scn*
113 find_data_section(Elf* elf_handle);
114 
115 Elf_Scn*
116 find_data1_section(Elf* elf_handle);
117 
118 Elf_Scn*
119 find_opd_section(Elf* elf_handle);
120 
121 bool
122 get_symbol_versionning_sections(Elf*		elf_handle,
123 				Elf_Scn*&	versym_section,
124 				Elf_Scn*&	verdef_section,
125 				Elf_Scn*&	verneed_section);
126 
127 Elf_Scn*
128 find_ksymtab_section(Elf* elf_handle);
129 
130 Elf_Scn*
131 find_ksymtab_gpl_section(Elf* elf_handle);
132 
133 Elf_Scn*
134 find_ksymtab_strings_section(Elf *elf_handle);
135 
136 Elf_Scn*
137 find_relocation_section(Elf* elf_handle, Elf_Scn* target_section);
138 
139 Elf_Scn*
140 find_strtab_for_symtab_section(Elf*	elf_handle,
141                                Elf_Scn*	symtab_section);
142 
143 //
144 // Helpers for symbol versioning
145 //
146 
147 bool
148 get_version_definition_for_versym(Elf*			 elf_handle,
149 				  GElf_Versym*		 versym,
150 				  Elf_Scn*		 verdef_section,
151 				  elf_symbol::version&	 version);
152 
153 bool
154 get_version_needed_for_versym(Elf*			elf_handle,
155 			      GElf_Versym*		versym,
156 			      Elf_Scn*			verneed_section,
157 			      elf_symbol::version&	version);
158 
159 bool
160 get_version_for_symbol(Elf*			elf_handle,
161 		       size_t			symbol_index,
162 		       bool			get_def_version,
163 		       elf_symbol::version&	version);
164 
165 bool
166 get_crc_for_symbol(Elf* elf_handle, GElf_Sym* crc_symbol, uint32_t& crc_value);
167 
168 //
169 // Architecture specific helpers
170 //
171 bool
172 architecture_is_ppc64(Elf* elf_handle);
173 
174 bool
175 architecture_is_ppc32(Elf* elf_handle);
176 
177 bool
178 architecture_is_arm32(Elf* elf_handle);
179 
180 bool
181 architecture_is_arm64(Elf* elf_handle);
182 
183 bool
184 architecture_is_big_endian(Elf* elf_handle);
185 
186 GElf_Addr
187 lookup_ppc64_elf_fn_entry_point_address(Elf*	  elf_handle,
188 					GElf_Addr fn_desc_address);
189 
190 //
191 // Helpers for Linux Kernel Binaries
192 //
193 
194 bool
195 is_linux_kernel_module(Elf *elf_handle);
196 
197 bool
198 is_linux_kernel(Elf *elf_handle);
199 
200 //
201 // elfutils helpers
202 //
203 
204 const Dwfl_Callbacks&
205 initialize_dwfl_callbacks(Dwfl_Callbacks&, char**);
206 
207 dwfl_sptr
208 create_new_dwfl_handle(Dwfl_Callbacks&);
209 
210 //
211 // Misc Helpers
212 //
213 
214 bool
215 get_binary_load_address(Elf* elf_handle, GElf_Addr& load_address);
216 
217 unsigned char
218 get_architecture_word_size(Elf* elf_handle);
219 
220 bool
221 is_executable(Elf* elf_handle);
222 
223 bool
224 is_dso(Elf* elf_handle);
225 
226 GElf_Addr
227 maybe_adjust_et_rel_sym_addr_to_abs_addr(Elf* elf_handle, GElf_Sym* sym);
228 
229 bool
230 address_is_in_opd_section(Elf* elf_handle, Dwarf_Addr addr);
231 
232 bool
233 lookup_data_tag_from_dynamic_segment(Elf*                       elf,
234                                      Elf64_Sxword               data_tag,
235                                      vector<string>&            dt_tag_data);
236 
237 bool
238 get_soname_of_elf_file(const string& path, string &soname);
239 } // end namespace elf_helpers
240 } // end namespace abigail
241 
242 #endif // __ABG_ELF_HELPERS_H__
243