1 /*
2 * Copyright (C) 2016 The Android Open Source Project
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * * Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * * Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in
12 * the documentation and/or other materials provided with the
13 * distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #ifndef __LINKER_SOINFO_H
30 #define __LINKER_SOINFO_H
31
32 #include <link.h>
33
34 #include <string>
35
36 #include "linker_namespaces.h"
37
38 #define FLAG_LINKED 0x00000001
39 #define FLAG_EXE 0x00000004 // The main executable
40 #define FLAG_LINKER 0x00000010 // The linker itself
41 #define FLAG_GNU_HASH 0x00000040 // uses gnu hash
42 #define FLAG_MAPPED_BY_CALLER 0x00000080 // the map is reserved by the caller
43 // and should not be unmapped
44 #define FLAG_NEW_SOINFO 0x40000000 // new soinfo format
45
46 #define SOINFO_VERSION 3
47
48 typedef void (*linker_dtor_function_t)();
49 typedef void (*linker_ctor_function_t)(int, char**, char**);
50
51 class SymbolName {
52 public:
SymbolName(const char * name)53 explicit SymbolName(const char* name)
54 : name_(name), has_elf_hash_(false), has_gnu_hash_(false),
55 elf_hash_(0), gnu_hash_(0) { }
56
get_name()57 const char* get_name() {
58 return name_;
59 }
60
61 uint32_t elf_hash();
62 uint32_t gnu_hash();
63
64 private:
65 const char* name_;
66 bool has_elf_hash_;
67 bool has_gnu_hash_;
68 uint32_t elf_hash_;
69 uint32_t gnu_hash_;
70
71 DISALLOW_IMPLICIT_CONSTRUCTORS(SymbolName);
72 };
73
74 struct version_info {
version_infoversion_info75 constexpr version_info() : elf_hash(0), name(nullptr), target_si(nullptr) {}
76
77 uint32_t elf_hash;
78 const char* name;
79 const soinfo* target_si;
80 };
81
82 // TODO(dimitry): remove reference from soinfo member functions to this class.
83 class VersionTracker;
84
85 #if defined(__work_around_b_24465209__)
86 #define SOINFO_NAME_LEN 128
87 #endif
88
89 struct soinfo {
90 #if defined(__work_around_b_24465209__)
91 private:
92 char old_name_[SOINFO_NAME_LEN];
93 #endif
94 public:
95 const ElfW(Phdr)* phdr;
96 size_t phnum;
97 #if defined(__work_around_b_24465209__)
98 ElfW(Addr) unused0; // DO NOT USE, maintained for compatibility.
99 #endif
100 ElfW(Addr) base;
101 size_t size;
102
103 #if defined(__work_around_b_24465209__)
104 uint32_t unused1; // DO NOT USE, maintained for compatibility.
105 #endif
106
107 ElfW(Dyn)* dynamic;
108
109 #if defined(__work_around_b_24465209__)
110 uint32_t unused2; // DO NOT USE, maintained for compatibility
111 uint32_t unused3; // DO NOT USE, maintained for compatibility
112 #endif
113
114 soinfo* next;
115 private:
116 uint32_t flags_;
117
118 const char* strtab_;
119 ElfW(Sym)* symtab_;
120
121 size_t nbucket_;
122 size_t nchain_;
123 uint32_t* bucket_;
124 uint32_t* chain_;
125
126 #if defined(__mips__) || !defined(__LP64__)
127 // This is only used by mips and mips64, but needs to be here for
128 // all 32-bit architectures to preserve binary compatibility.
129 ElfW(Addr)** plt_got_;
130 #endif
131
132 #if defined(USE_RELA)
133 ElfW(Rela)* plt_rela_;
134 size_t plt_rela_count_;
135
136 ElfW(Rela)* rela_;
137 size_t rela_count_;
138 #else
139 ElfW(Rel)* plt_rel_;
140 size_t plt_rel_count_;
141
142 ElfW(Rel)* rel_;
143 size_t rel_count_;
144 #endif
145
146 linker_ctor_function_t* preinit_array_;
147 size_t preinit_array_count_;
148
149 linker_ctor_function_t* init_array_;
150 size_t init_array_count_;
151 linker_dtor_function_t* fini_array_;
152 size_t fini_array_count_;
153
154 linker_ctor_function_t init_func_;
155 linker_dtor_function_t fini_func_;
156
157 #if defined(__arm__)
158 public:
159 // ARM EABI section used for stack unwinding.
160 uint32_t* ARM_exidx;
161 size_t ARM_exidx_count;
162 private:
163 #elif defined(__mips__)
164 uint32_t mips_symtabno_;
165 uint32_t mips_local_gotno_;
166 uint32_t mips_gotsym_;
167 bool mips_relocate_got(const VersionTracker& version_tracker,
168 const soinfo_list_t& global_group,
169 const soinfo_list_t& local_group);
170 #if !defined(__LP64__)
171 bool mips_check_and_adjust_fp_modes();
172 #endif
173 #endif
174 size_t ref_count_;
175 public:
176 link_map link_map_head;
177
178 bool constructors_called;
179
180 // When you read a virtual address from the ELF file, add this
181 // value to get the corresponding address in the process' address space.
182 ElfW(Addr) load_bias;
183
184 #if !defined(__LP64__)
185 bool has_text_relocations;
186 #endif
187 bool has_DT_SYMBOLIC;
188
189 public:
190 soinfo(android_namespace_t* ns, const char* name, const struct stat* file_stat,
191 off64_t file_offset, int rtld_flags);
192 ~soinfo();
193
194 void call_constructors();
195 void call_destructors();
196 void call_pre_init_constructors();
197 bool prelink_image();
198 bool link_image(const soinfo_list_t& global_group, const soinfo_list_t& local_group,
199 const android_dlextinfo* extinfo);
200 bool protect_relro();
201
202 void add_child(soinfo* child);
203 void remove_all_links();
204
205 ino_t get_st_ino() const;
206 dev_t get_st_dev() const;
207 off64_t get_file_offset() const;
208
209 uint32_t get_rtld_flags() const;
210 uint32_t get_dt_flags_1() const;
211 void set_dt_flags_1(uint32_t dt_flags_1);
212
213 soinfo_list_t& get_children();
214 const soinfo_list_t& get_children() const;
215
216 soinfo_list_t& get_parents();
217
218 bool find_symbol_by_name(SymbolName& symbol_name,
219 const version_info* vi,
220 const ElfW(Sym)** symbol) const;
221
222 ElfW(Sym)* find_symbol_by_address(const void* addr);
223 ElfW(Addr) resolve_symbol_address(const ElfW(Sym)* s) const;
224
225 const char* get_string(ElfW(Word) index) const;
226 bool can_unload() const;
227 bool is_gnu_hash() const;
228
has_min_versionsoinfo229 bool inline has_min_version(uint32_t min_version __unused) const {
230 #if defined(__work_around_b_24465209__)
231 return (flags_ & FLAG_NEW_SOINFO) != 0 && version_ >= min_version;
232 #else
233 return true;
234 #endif
235 }
236
237 bool is_linked() const;
238 bool is_linker() const;
239 bool is_main_executable() const;
240
241 void set_linked();
242 void set_linker_flag();
243 void set_main_executable();
244 void set_nodelete();
245
246 void increment_ref_count();
247 size_t decrement_ref_count();
248
249 soinfo* get_local_group_root() const;
250
251 void set_soname(const char* soname);
252 const char* get_soname() const;
253 const char* get_realpath() const;
254 const ElfW(Versym)* get_versym(size_t n) const;
255 ElfW(Addr) get_verneed_ptr() const;
256 size_t get_verneed_cnt() const;
257 ElfW(Addr) get_verdef_ptr() const;
258 size_t get_verdef_cnt() const;
259
260 uint32_t get_target_sdk_version() const;
261
262 void set_dt_runpath(const char *);
263 const std::vector<std::string>& get_dt_runpath() const;
264 android_namespace_t* get_primary_namespace();
265 void add_secondary_namespace(android_namespace_t* secondary_ns);
266 android_namespace_list_t& get_secondary_namespaces();
267
268 void set_mapped_by_caller(bool reserved_map);
269 bool is_mapped_by_caller() const;
270
271 uintptr_t get_handle() const;
272 void generate_handle();
273 void* to_handle();
274
275 private:
276 bool elf_lookup(SymbolName& symbol_name, const version_info* vi, uint32_t* symbol_index) const;
277 ElfW(Sym)* elf_addr_lookup(const void* addr);
278 bool gnu_lookup(SymbolName& symbol_name, const version_info* vi, uint32_t* symbol_index) const;
279 ElfW(Sym)* gnu_addr_lookup(const void* addr);
280
281 bool lookup_version_info(const VersionTracker& version_tracker, ElfW(Word) sym,
282 const char* sym_name, const version_info** vi);
283
284 template<typename ElfRelIteratorT>
285 bool relocate(const VersionTracker& version_tracker, ElfRelIteratorT&& rel_iterator,
286 const soinfo_list_t& global_group, const soinfo_list_t& local_group);
287
288 private:
289 // This part of the structure is only available
290 // when FLAG_NEW_SOINFO is set in this->flags.
291 uint32_t version_;
292
293 // version >= 0
294 dev_t st_dev_;
295 ino_t st_ino_;
296
297 // dependency graph
298 soinfo_list_t children_;
299 soinfo_list_t parents_;
300
301 // version >= 1
302 off64_t file_offset_;
303 uint32_t rtld_flags_;
304 uint32_t dt_flags_1_;
305 size_t strtab_size_;
306
307 // version >= 2
308
309 size_t gnu_nbucket_;
310 uint32_t* gnu_bucket_;
311 uint32_t* gnu_chain_;
312 uint32_t gnu_maskwords_;
313 uint32_t gnu_shift2_;
314 ElfW(Addr)* gnu_bloom_filter_;
315
316 soinfo* local_group_root_;
317
318 uint8_t* android_relocs_;
319 size_t android_relocs_size_;
320
321 const char* soname_;
322 std::string realpath_;
323
324 const ElfW(Versym)* versym_;
325
326 ElfW(Addr) verdef_ptr_;
327 size_t verdef_cnt_;
328
329 ElfW(Addr) verneed_ptr_;
330 size_t verneed_cnt_;
331
332 uint32_t target_sdk_version_;
333
334 // version >= 3
335 std::vector<std::string> dt_runpath_;
336 android_namespace_t* primary_namespace_;
337 android_namespace_list_t secondary_namespaces_;
338 uintptr_t handle_;
339
340 friend soinfo* get_libdl_info(const char* linker_path);
341 };
342
343 // This function is used by dlvsym() to calculate hash of sym_ver
344 uint32_t calculate_elf_hash(const char* name);
345
346 const char* fix_dt_needed(const char* dt_needed, const char* sopath);
347
348 template<typename F>
for_each_dt_needed(const soinfo * si,F action)349 void for_each_dt_needed(const soinfo* si, F action) {
350 for (const ElfW(Dyn)* d = si->dynamic; d->d_tag != DT_NULL; ++d) {
351 if (d->d_tag == DT_NEEDED) {
352 action(fix_dt_needed(si->get_string(d->d_un.d_val), si->get_realpath()));
353 }
354 }
355 }
356
357 #endif /* __LINKER_SOINFO_H */
358