1/* Program and address space management, for GDB, the GNU debugger. 2 3 Copyright (C) 2009-2020 Free Software Foundation, Inc. 4 5 This file is part of GDB. 6 7 This program is free software; you can redistribute it and/or modify 8 it under the terms of the GNU General Public License as published by 9 the Free Software Foundation; either version 3 of the License, or 10 (at your option) any later version. 11 12 This program is distributed in the hope that it will be useful, 13 but WITHOUT ANY WARRANTY; without even the implied warranty of 14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 GNU General Public License for more details. 16 17 You should have received a copy of the GNU General Public License 18 along with this program. If not, see <http://www.gnu.org/licenses/>. */ 19 20 21#ifndef PROGSPACE_H 22#define PROGSPACE_H 23 24#include "target.h" 25#include "gdb_bfd.h" 26#include "gdbsupport/gdb_vecs.h" 27#include "registry.h" 28#include "gdbsupport/next-iterator.h" 29#include "gdbsupport/safe-iterator.h" 30#include <list> 31#include <vector> 32 33struct target_ops; 34struct bfd; 35struct objfile; 36struct inferior; 37struct exec; 38struct address_space; 39struct program_space_data; 40struct address_space_data; 41struct so_list; 42 43typedef std::list<std::shared_ptr<objfile>> objfile_list; 44 45/* An iterator that wraps an iterator over std::shared_ptr<objfile>, 46 and dereferences the returned object. This is useful for iterating 47 over a list of shared pointers and returning raw pointers -- which 48 helped avoid touching a lot of code when changing how objfiles are 49 managed. */ 50 51class unwrapping_objfile_iterator 52{ 53public: 54 55 typedef unwrapping_objfile_iterator self_type; 56 typedef typename ::objfile *value_type; 57 typedef typename ::objfile &reference; 58 typedef typename ::objfile **pointer; 59 typedef typename objfile_list::iterator::iterator_category iterator_category; 60 typedef typename objfile_list::iterator::difference_type difference_type; 61 62 unwrapping_objfile_iterator (const objfile_list::iterator &iter) 63 : m_iter (iter) 64 { 65 } 66 67 objfile *operator* () const 68 { 69 return m_iter->get (); 70 } 71 72 unwrapping_objfile_iterator operator++ () 73 { 74 ++m_iter; 75 return *this; 76 } 77 78 bool operator!= (const unwrapping_objfile_iterator &other) const 79 { 80 return m_iter != other.m_iter; 81 } 82 83private: 84 85 /* The underlying iterator. */ 86 objfile_list::iterator m_iter; 87}; 88 89 90/* A range that returns unwrapping_objfile_iterators. */ 91 92struct unwrapping_objfile_range 93{ 94 typedef unwrapping_objfile_iterator iterator; 95 96 unwrapping_objfile_range (objfile_list &ol) 97 : m_list (ol) 98 { 99 } 100 101 iterator begin () const 102 { 103 return iterator (m_list.begin ()); 104 } 105 106 iterator end () const 107 { 108 return iterator (m_list.end ()); 109 } 110 111private: 112 113 objfile_list &m_list; 114}; 115 116/* A program space represents a symbolic view of an address space. 117 Roughly speaking, it holds all the data associated with a 118 non-running-yet program (main executable, main symbols), and when 119 an inferior is running and is bound to it, includes the list of its 120 mapped in shared libraries. 121 122 In the traditional debugging scenario, there's a 1-1 correspondence 123 among program spaces, inferiors and address spaces, like so: 124 125 pspace1 (prog1) <--> inf1(pid1) <--> aspace1 126 127 In the case of debugging more than one traditional unix process or 128 program, we still have: 129 130 |-----------------+------------+---------| 131 | pspace1 (prog1) | inf1(pid1) | aspace1 | 132 |----------------------------------------| 133 | pspace2 (prog1) | no inf yet | aspace2 | 134 |-----------------+------------+---------| 135 | pspace3 (prog2) | inf2(pid2) | aspace3 | 136 |-----------------+------------+---------| 137 138 In the former example, if inf1 forks (and GDB stays attached to 139 both processes), the new child will have its own program and 140 address spaces. Like so: 141 142 |-----------------+------------+---------| 143 | pspace1 (prog1) | inf1(pid1) | aspace1 | 144 |-----------------+------------+---------| 145 | pspace2 (prog1) | inf2(pid2) | aspace2 | 146 |-----------------+------------+---------| 147 148 However, had inf1 from the latter case vforked instead, it would 149 share the program and address spaces with its parent, until it 150 execs or exits, like so: 151 152 |-----------------+------------+---------| 153 | pspace1 (prog1) | inf1(pid1) | aspace1 | 154 | | inf2(pid2) | | 155 |-----------------+------------+---------| 156 157 When the vfork child execs, it is finally given new program and 158 address spaces. 159 160 |-----------------+------------+---------| 161 | pspace1 (prog1) | inf1(pid1) | aspace1 | 162 |-----------------+------------+---------| 163 | pspace2 (prog1) | inf2(pid2) | aspace2 | 164 |-----------------+------------+---------| 165 166 There are targets where the OS (if any) doesn't provide memory 167 management or VM protection, where all inferiors share the same 168 address space --- e.g. uClinux. GDB models this by having all 169 inferiors share the same address space, but, giving each its own 170 program space, like so: 171 172 |-----------------+------------+---------| 173 | pspace1 (prog1) | inf1(pid1) | | 174 |-----------------+------------+ | 175 | pspace2 (prog1) | inf2(pid2) | aspace1 | 176 |-----------------+------------+ | 177 | pspace3 (prog2) | inf3(pid3) | | 178 |-----------------+------------+---------| 179 180 The address space sharing matters for run control and breakpoints 181 management. E.g., did we just hit a known breakpoint that we need 182 to step over? Is this breakpoint a duplicate of this other one, or 183 do I need to insert a trap? 184 185 Then, there are targets where all symbols look the same for all 186 inferiors, although each has its own address space, as e.g., 187 Ericsson DICOS. In such case, the model is: 188 189 |---------+------------+---------| 190 | | inf1(pid1) | aspace1 | 191 | +------------+---------| 192 | pspace | inf2(pid2) | aspace2 | 193 | +------------+---------| 194 | | inf3(pid3) | aspace3 | 195 |---------+------------+---------| 196 197 Note however, that the DICOS debug API takes care of making GDB 198 believe that breakpoints are "global". That is, although each 199 process does have its own private copy of data symbols (just like a 200 bunch of forks), to the breakpoints module, all processes share a 201 single address space, so all breakpoints set at the same address 202 are duplicates of each other, even breakpoints set in the data 203 space (e.g., call dummy breakpoints placed on stack). This allows 204 a simplification in the spaces implementation: we avoid caring for 205 a many-many links between address and program spaces. Either 206 there's a single address space bound to the program space 207 (traditional unix/uClinux), or, in the DICOS case, the address 208 space bound to the program space is mostly ignored. */ 209 210/* The program space structure. */ 211 212struct program_space 213{ 214 /* Constructs a new empty program space, binds it to ASPACE, and 215 adds it to the program space list. */ 216 explicit program_space (address_space *aspace); 217 218 /* Releases a program space, and all its contents (shared libraries, 219 objfiles, and any other references to the program space in other 220 modules). It is an internal error to call this when the program 221 space is the current program space, since there should always be 222 a program space. */ 223 ~program_space (); 224 225 typedef unwrapping_objfile_range objfiles_range; 226 227 /* Return an iterable object that can be used to iterate over all 228 objfiles. The basic use is in a foreach, like: 229 230 for (objfile *objf : pspace->objfiles ()) { ... } */ 231 objfiles_range objfiles () 232 { 233 return unwrapping_objfile_range (objfiles_list); 234 } 235 236 typedef basic_safe_range<objfiles_range> objfiles_safe_range; 237 238 /* An iterable object that can be used to iterate over all objfiles. 239 The basic use is in a foreach, like: 240 241 for (objfile *objf : pspace->objfiles_safe ()) { ... } 242 243 This variant uses a basic_safe_iterator so that objfiles can be 244 deleted during iteration. */ 245 objfiles_safe_range objfiles_safe () 246 { 247 return objfiles_safe_range (objfiles_list); 248 } 249 250 /* Add OBJFILE to the list of objfiles, putting it just before 251 BEFORE. If BEFORE is nullptr, it will go at the end of the 252 list. */ 253 void add_objfile (std::shared_ptr<objfile> &&objfile, 254 struct objfile *before); 255 256 /* Remove OBJFILE from the list of objfiles. */ 257 void remove_objfile (struct objfile *objfile); 258 259 /* Return true if there is more than one object file loaded; false 260 otherwise. */ 261 bool multi_objfile_p () const 262 { 263 return objfiles_list.size () > 1; 264 } 265 266 /* Free all the objfiles associated with this program space. */ 267 void free_all_objfiles (); 268 269 /* Return a range adapter for iterating over all the solibs in this 270 program space. Use it like: 271 272 for (so_list *so : pspace->solibs ()) { ... } */ 273 next_adapter<struct so_list> solibs () const; 274 275 276 /* Unique ID number. */ 277 int num = 0; 278 279 /* The main executable loaded into this program space. This is 280 managed by the exec target. */ 281 282 /* The BFD handle for the main executable. */ 283 bfd *ebfd = NULL; 284 /* The last-modified time, from when the exec was brought in. */ 285 long ebfd_mtime = 0; 286 /* Similar to bfd_get_filename (exec_bfd) but in original form given 287 by user, without symbolic links and pathname resolved. 288 It needs to be freed by xfree. It is not NULL iff EBFD is not NULL. */ 289 char *pspace_exec_filename = NULL; 290 291 /* Binary file diddling handle for the core file. */ 292 gdb_bfd_ref_ptr cbfd; 293 294 /* The address space attached to this program space. More than one 295 program space may be bound to the same address space. In the 296 traditional unix-like debugging scenario, this will usually 297 match the address space bound to the inferior, and is mostly 298 used by the breakpoints module for address matches. If the 299 target shares a program space for all inferiors and breakpoints 300 are global, then this field is ignored (we don't currently 301 support inferiors sharing a program space if the target doesn't 302 make breakpoints global). */ 303 struct address_space *aspace = NULL; 304 305 /* True if this program space's section offsets don't yet represent 306 the final offsets of the "live" address space (that is, the 307 section addresses still require the relocation offsets to be 308 applied, and hence we can't trust the section addresses for 309 anything that pokes at live memory). E.g., for qOffsets 310 targets, or for PIE executables, until we connect and ask the 311 target for the final relocation offsets, the symbols we've used 312 to set breakpoints point at the wrong addresses. */ 313 int executing_startup = 0; 314 315 /* True if no breakpoints should be inserted in this program 316 space. */ 317 int breakpoints_not_allowed = 0; 318 319 /* The object file that the main symbol table was loaded from 320 (e.g. the argument to the "symbol-file" or "file" command). */ 321 struct objfile *symfile_object_file = NULL; 322 323 /* All known objfiles are kept in a linked list. */ 324 std::list<std::shared_ptr<objfile>> objfiles_list; 325 326 /* The set of target sections matching the sections mapped into 327 this program space. Managed by both exec_ops and solib.c. */ 328 struct target_section_table target_sections {}; 329 330 /* List of shared objects mapped into this space. Managed by 331 solib.c. */ 332 struct so_list *so_list = NULL; 333 334 /* Number of calls to solib_add. */ 335 unsigned int solib_add_generation = 0; 336 337 /* When an solib is added, it is also added to this vector. This 338 is so we can properly report solib changes to the user. */ 339 std::vector<struct so_list *> added_solibs; 340 341 /* When an solib is removed, its name is added to this vector. 342 This is so we can properly report solib changes to the user. */ 343 std::vector<std::string> deleted_solibs; 344 345 /* Per pspace data-pointers required by other GDB modules. */ 346 REGISTRY_FIELDS {}; 347}; 348 349/* An address space. It is used for comparing if 350 pspaces/inferior/threads see the same address space and for 351 associating caches to each address space. */ 352struct address_space 353{ 354 int num; 355 356 /* Per aspace data-pointers required by other GDB modules. */ 357 REGISTRY_FIELDS; 358}; 359 360/* The object file that the main symbol table was loaded from (e.g. the 361 argument to the "symbol-file" or "file" command). */ 362 363#define symfile_objfile current_program_space->symfile_object_file 364 365/* The set of target sections matching the sections mapped into the 366 current program space. */ 367#define current_target_sections (¤t_program_space->target_sections) 368 369/* The list of all program spaces. There's always at least one. */ 370extern std::vector<struct program_space *>program_spaces; 371 372/* The current program space. This is always non-null. */ 373extern struct program_space *current_program_space; 374 375/* Returns true iff there's no inferior bound to PSPACE. */ 376extern int program_space_empty_p (struct program_space *pspace); 377 378/* Copies program space SRC to DEST. Copies the main executable file, 379 and the main symbol file. Returns DEST. */ 380extern struct program_space *clone_program_space (struct program_space *dest, 381 struct program_space *src); 382 383/* Sets PSPACE as the current program space. This is usually used 384 instead of set_current_space_and_thread when the current 385 thread/inferior is not important for the operations that follow. 386 E.g., when accessing the raw symbol tables. If memory access is 387 required, then you should use switch_to_program_space_and_thread. 388 Otherwise, it is the caller's responsibility to make sure that the 389 currently selected inferior/thread matches the selected program 390 space. */ 391extern void set_current_program_space (struct program_space *pspace); 392 393/* Save/restore the current program space. */ 394 395class scoped_restore_current_program_space 396{ 397public: 398 scoped_restore_current_program_space () 399 : m_saved_pspace (current_program_space) 400 {} 401 402 ~scoped_restore_current_program_space () 403 { set_current_program_space (m_saved_pspace); } 404 405 DISABLE_COPY_AND_ASSIGN (scoped_restore_current_program_space); 406 407private: 408 program_space *m_saved_pspace; 409}; 410 411/* Create a new address space object, and add it to the list. */ 412extern struct address_space *new_address_space (void); 413 414/* Maybe create a new address space object, and add it to the list, or 415 return a pointer to an existing address space, in case inferiors 416 share an address space. */ 417extern struct address_space *maybe_new_address_space (void); 418 419/* Returns the integer address space id of ASPACE. */ 420extern int address_space_num (struct address_space *aspace); 421 422/* Update all program spaces matching to address spaces. The user may 423 have created several program spaces, and loaded executables into 424 them before connecting to the target interface that will create the 425 inferiors. All that happens before GDB has a chance to know if the 426 inferiors will share an address space or not. Call this after 427 having connected to the target interface and having fetched the 428 target description, to fixup the program/address spaces 429 mappings. */ 430extern void update_address_spaces (void); 431 432/* Reset saved solib data at the start of an solib event. This lets 433 us properly collect the data when calling solib_add, so it can then 434 later be printed. */ 435extern void clear_program_space_solib_cache (struct program_space *); 436 437/* Keep a registry of per-pspace data-pointers required by other GDB 438 modules. */ 439 440DECLARE_REGISTRY (program_space); 441 442/* Keep a registry of per-aspace data-pointers required by other GDB 443 modules. */ 444 445DECLARE_REGISTRY (address_space); 446 447#endif 448