gdbserver/target.cc

   1 /* Target operations for the remote server for GDB.
   2    Copyright (C) 2002-2020 Free Software Foundation, Inc.
   3
   4    Contributed by MontaVista Software.
   5
   6    This file is part of GDB.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  20
  21 #include "server.h"
  22 #include "tracepoint.h"
  23 #include "gdbsupport/byte-vector.h"
  24 #include "hostio.h"
  25
  26 process_stratum_target *the_target;
  27
  28 int
  29 set_desired_thread ()
  30 {
  31   client_state &cs = get_client_state ();
  32   thread_info *found = find_thread_ptid (cs.general_thread);
  33
  34   current_thread = found;
  35   return (current_thread != NULL);
  36 }
  37
  38 /* The thread that was current before prepare_to_access_memory was
  39    called.  done_accessing_memory uses this to restore the previous
  40    selected thread.  */
  41 static ptid_t prev_general_thread;
  42
  43 /* See target.h.  */
  44
  45 int
  46 prepare_to_access_memory (void)
  47 {
  48   client_state &cs = get_client_state ();
  49
  50   /* The first thread found.  */
  51   struct thread_info *first = NULL;
  52   /* The first stopped thread found.  */
  53   struct thread_info *stopped = NULL;
  54   /* The current general thread, if found.  */
  55   struct thread_info *current = NULL;
  56
  57   /* Save the general thread value, since prepare_to_access_memory could change
  58      it.  */
  59   prev_general_thread = cs.general_thread;
  60
  61   int res = the_target->pt->prepare_to_access_memory ();
  62   if (res != 0)
  63     return res;
  64
  65   for_each_thread (prev_general_thread.pid (), [&] (thread_info *thread)
  66     {
  67       if (mythread_alive (thread->id))
  68         {
  69           if (stopped == NULL && the_target->pt->supports_thread_stopped ()
  70               && target_thread_stopped (thread))
  71             stopped = thread;
  72
  73           if (first == NULL)
  74             first = thread;
  75
  76           if (current == NULL && prev_general_thread == thread->id)
  77             current = thread;
  78         }
  79     });
  80
  81   /* The thread we end up choosing.  */
  82   struct thread_info *thread;
  83
  84   /* Prefer a stopped thread.  If none is found, try the current
  85      thread.  Otherwise, take the first thread in the process.  If
  86      none is found, undo the effects of
  87      target->prepare_to_access_memory() and return error.  */
  88   if (stopped != NULL)
  89     thread = stopped;
  90   else if (current != NULL)
  91     thread = current;
  92   else if (first != NULL)
  93     thread = first;
  94   else
  95     {
  96       done_accessing_memory ();
  97       return 1;
  98     }
  99
 100   current_thread = thread;
 101   cs.general_thread = ptid_of (thread);
 102
 103   return 0;
 104 }
 105
 106 /* See target.h.  */
 107
 108 void
 109 done_accessing_memory (void)
 110 {
 111   client_state &cs = get_client_state ();
 112
 113   the_target->pt->done_accessing_memory ();
 114
 115   /* Restore the previous selected thread.  */
 116   cs.general_thread = prev_general_thread;
 117   switch_to_thread (the_target, cs.general_thread);
 118 }
 119
 120 int
 121 read_inferior_memory (CORE_ADDR memaddr, unsigned char *myaddr, int len)
 122 {
 123   int res;
 124   res = the_target->pt->read_memory (memaddr, myaddr, len);
 125   check_mem_read (memaddr, myaddr, len);
 126   return res;
 127 }
 128
 129 /* See target/target.h.  */
 130
 131 int
 132 target_read_memory (CORE_ADDR memaddr, gdb_byte *myaddr, ssize_t len)
 133 {
 134   return read_inferior_memory (memaddr, myaddr, len);
 135 }
 136
 137 /* See target/target.h.  */
 138
 139 int
 140 target_read_uint32 (CORE_ADDR memaddr, uint32_t *result)
 141 {
 142   return read_inferior_memory (memaddr, (gdb_byte *) result, sizeof (*result));
 143 }
 144
 145 /* See target/target.h.  */
 146
 147 int
 148 target_write_memory (CORE_ADDR memaddr, const unsigned char *myaddr,
 149                      ssize_t len)
 150 {
 151   /* Make a copy of the data because check_mem_write may need to
 152      update it.  */
 153   gdb::byte_vector buffer (myaddr, myaddr + len);
 154   check_mem_write (memaddr, buffer.data (), myaddr, len);
 155   return the_target->pt->write_memory (memaddr, buffer.data (), len);
 156 }
 157
 158 ptid_t
 159 mywait (ptid_t ptid, struct target_waitstatus *ourstatus, int options,
 160         int connected_wait)
 161 {
 162   ptid_t ret;
 163
 164   if (connected_wait)
 165     server_waiting = 1;
 166
 167   ret = target_wait (ptid, ourstatus, options);
 168
 169   /* We don't expose _LOADED events to gdbserver core.  See the
 170      `dlls_changed' global.  */
 171   if (ourstatus->kind == TARGET_WAITKIND_LOADED)
 172     ourstatus->kind = TARGET_WAITKIND_STOPPED;
 173
 174   /* If GDB is connected through TCP/serial, then GDBserver will most
 175      probably be running on its own terminal/console, so it's nice to
 176      print there why is GDBserver exiting.  If however, GDB is
 177      connected through stdio, then there's no need to spam the GDB
 178      console with this -- the user will already see the exit through
 179      regular GDB output, in that same terminal.  */
 180   if (!remote_connection_is_stdio ())
 181     {
 182       if (ourstatus->kind == TARGET_WAITKIND_EXITED)
 183         fprintf (stderr,
 184                  "\nChild exited with status %d\n", ourstatus->value.integer);
 185       else if (ourstatus->kind == TARGET_WAITKIND_SIGNALLED)
 186         fprintf (stderr, "\nChild terminated with signal = 0x%x (%s)\n",
 187                  gdb_signal_to_host (ourstatus->value.sig),
 188                  gdb_signal_to_name (ourstatus->value.sig));
 189     }
 190
 191   if (connected_wait)
 192     server_waiting = 0;
 193
 194   return ret;
 195 }
 196
 197 /* See target/target.h.  */
 198
 199 void
 200 target_stop_and_wait (ptid_t ptid)
 201 {
 202   struct target_waitstatus status;
 203   bool was_non_stop = non_stop;
 204   struct thread_resume resume_info;
 205
 206   resume_info.thread = ptid;
 207   resume_info.kind = resume_stop;
 208   resume_info.sig = GDB_SIGNAL_0;
 209   the_target->pt->resume (&resume_info, 1);
 210
 211   non_stop = true;
 212   mywait (ptid, &status, 0, 0);
 213   non_stop = was_non_stop;
 214 }
 215
 216 /* See target/target.h.  */
 217
 218 ptid_t
 219 target_wait (ptid_t ptid, struct target_waitstatus *status, int options)
 220 {
 221   return the_target->pt->wait (ptid, status, options);
 222 }
 223
 224 /* See target/target.h.  */
 225
 226 void
 227 target_mourn_inferior (ptid_t ptid)
 228 {
 229   the_target->pt->mourn (find_process_pid (ptid.pid ()));
 230 }
 231
 232 /* See target/target.h.  */
 233
 234 void
 235 target_continue_no_signal (ptid_t ptid)
 236 {
 237   struct thread_resume resume_info;
 238
 239   resume_info.thread = ptid;
 240   resume_info.kind = resume_continue;
 241   resume_info.sig = GDB_SIGNAL_0;
 242   the_target->pt->resume (&resume_info, 1);
 243 }
 244
 245 /* See target/target.h.  */
 246
 247 void
 248 target_continue (ptid_t ptid, enum gdb_signal signal)
 249 {
 250   struct thread_resume resume_info;
 251
 252   resume_info.thread = ptid;
 253   resume_info.kind = resume_continue;
 254   resume_info.sig = gdb_signal_to_host (signal);
 255   the_target->pt->resume (&resume_info, 1);
 256 }
 257
 258 /* See target/target.h.  */
 259
 260 int
 261 target_supports_multi_process (void)
 262 {
 263   return the_target->pt->supports_multi_process ();
 264 }
 265
 266 void
 267 set_target_ops (process_stratum_target *target)
 268 {
 269   the_target = XNEW (process_stratum_target);
 270   memcpy (the_target, target, sizeof (*the_target));
 271 }
 272
 273 /* Convert pid to printable format.  */
 274
 275 const char *
 276 target_pid_to_str (ptid_t ptid)
 277 {
 278   static char buf[80];
 279
 280   if (ptid == minus_one_ptid)
 281     xsnprintf (buf, sizeof (buf), "<all threads>");
 282   else if (ptid == null_ptid)
 283     xsnprintf (buf, sizeof (buf), "<null thread>");
 284   else if (ptid.tid () != 0)
 285     xsnprintf (buf, sizeof (buf), "Thread %d.0x%lx",
 286                ptid.pid (), ptid.tid ());
 287   else if (ptid.lwp () != 0)
 288     xsnprintf (buf, sizeof (buf), "LWP %d.%ld",
 289                ptid.pid (), ptid.lwp ());
 290   else
 291     xsnprintf (buf, sizeof (buf), "Process %d",
 292                ptid.pid ());
 293
 294   return buf;
 295 }
 296
 297 int
 298 kill_inferior (process_info *proc)
 299 {
 300   gdb_agent_about_to_close (proc->pid);
 301
 302   return the_target->pt->kill (proc);
 303 }
 304
 305 /* Default implementation for breakpoint_kind_for_pc.
 306
 307    The default behavior for targets that don't implement breakpoint_kind_for_pc
 308    is to use the size of a breakpoint as the kind.  */
 309
 310 int
 311 default_breakpoint_kind_from_pc (CORE_ADDR *pcptr)
 312 {
 313   int size = 0;
 314
 315   gdb_assert (the_target->sw_breakpoint_from_kind != NULL);
 316
 317   (*the_target->sw_breakpoint_from_kind) (0, &size);
 318   return size;
 319 }
 320
 321 /* Define it.  */
 322
 323 target_terminal_state target_terminal::m_terminal_state
 324   = target_terminal_state::is_ours;
 325
 326 /* See target/target.h.  */
 327
 328 void
 329 target_terminal::init ()
 330 {
 331   /* Placeholder needed because of fork_inferior.  Not necessary on
 332      GDBserver.  */
 333 }
 334
 335 /* See target/target.h.  */
 336
 337 void
 338 target_terminal::inferior ()
 339 {
 340   /* Placeholder needed because of fork_inferior.  Not necessary on
 341      GDBserver.  */
 342 }
 343
 344 /* See target/target.h.  */
 345
 346 void
 347 target_terminal::ours ()
 348 {
 349   /* Placeholder needed because of fork_inferior.  Not necessary on
 350      GDBserver.  */
 351 }
 352
 353 /* See target/target.h.  */
 354
 355 void
 356 target_terminal::ours_for_output (void)
 357 {
 358   /* Placeholder.  */
 359 }
 360
 361 /* See target/target.h.  */
 362
 363 void
 364 target_terminal::info (const char *arg, int from_tty)
 365 {
 366   /* Placeholder.  */
 367 }
 368
 369 /* Default implementations of target ops.
 370    See target.h for definitions.  */
 371
 372 void
 373 process_target::post_create_inferior ()
 374 {
 375   /* Nop.  */
 376 }
 377
 378 int
 379 process_target::prepare_to_access_memory ()
 380 {
 381   return 0;
 382 }
 383
 384 void
 385 process_target::done_accessing_memory ()
 386 {
 387   /* Nop.  */
 388 }
 389
 390 void
 391 process_target::look_up_symbols ()
 392 {
 393   /* Nop.  */
 394 }
 395
 396 bool
 397 process_target::supports_read_auxv ()
 398 {
 399   return false;
 400 }
 401
 402 int
 403 process_target::read_auxv (CORE_ADDR offset, unsigned char *myaddr,
 404                            unsigned int len)
 405 {
 406   gdb_assert_not_reached ("target op read_auxv not supported");
 407 }
 408
 409 bool
 410 process_target::supports_z_point_type (char z_type)
 411 {
 412   return false;
 413 }
 414
 415 int
 416 process_target::insert_point (enum raw_bkpt_type type, CORE_ADDR addr,
 417                               int size, raw_breakpoint *bp)
 418 {
 419   return 1;
 420 }
 421
 422 int
 423 process_target::remove_point (enum raw_bkpt_type type, CORE_ADDR addr,
 424                               int size, raw_breakpoint *bp)
 425 {
 426   return 1;
 427 }
 428
 429 bool
 430 process_target::stopped_by_sw_breakpoint ()
 431 {
 432   return false;
 433 }
 434
 435 bool
 436 process_target::supports_stopped_by_sw_breakpoint ()
 437 {
 438   return false;
 439 }
 440
 441 bool
 442 process_target::stopped_by_hw_breakpoint ()
 443 {
 444   return false;
 445 }
 446
 447 bool
 448 process_target::supports_stopped_by_hw_breakpoint ()
 449 {
 450   return false;
 451 }
 452
 453 bool
 454 process_target::supports_hardware_single_step ()
 455 {
 456   return false;
 457 }
 458
 459 bool
 460 process_target::stopped_by_watchpoint ()
 461 {
 462   return false;
 463 }
 464
 465 CORE_ADDR
 466 process_target::stopped_data_address ()
 467 {
 468   return 0;
 469 }
 470
 471 bool
 472 process_target::supports_read_offsets ()
 473 {
 474   return false;
 475 }
 476
 477 int
 478 process_target::read_offsets (CORE_ADDR *text, CORE_ADDR *data)
 479 {
 480   gdb_assert_not_reached ("target op read_offsets not supported");
 481 }
 482
 483 bool
 484 process_target::supports_get_tls_address ()
 485 {
 486   return false;
 487 }
 488
 489 int
 490 process_target::get_tls_address (thread_info *thread, CORE_ADDR offset,
 491                                  CORE_ADDR load_module, CORE_ADDR *address)
 492 {
 493   gdb_assert_not_reached ("target op get_tls_address not supported");
 494 }
 495
 496 void
 497 process_target::hostio_last_error (char *buf)
 498 {
 499   hostio_last_error_from_errno (buf);
 500 }
 501
 502 bool
 503 process_target::supports_qxfer_osdata ()
 504 {
 505   return false;
 506 }
 507
 508 int
 509 process_target::qxfer_osdata (const char *annex, unsigned char *readbuf,
 510                               unsigned const char *writebuf,
 511                               CORE_ADDR offset, int len)
 512 {
 513   gdb_assert_not_reached ("target op qxfer_osdata not supported");
 514 }
 515
 516 bool
 517 process_target::supports_qxfer_siginfo ()
 518 {
 519   return false;
 520 }
 521
 522 int
 523 process_target::qxfer_siginfo (const char *annex, unsigned char *readbuf,
 524                                unsigned const char *writebuf,
 525                                CORE_ADDR offset, int len)
 526 {
 527   gdb_assert_not_reached ("target op qxfer_siginfo not supported");
 528 }
 529
 530 bool
 531 process_target::supports_non_stop ()
 532 {
 533   return false;
 534 }
 535
 536 bool
 537 process_target::async (bool enable)
 538 {
 539   return false;
 540 }
 541
 542 int
 543 process_target::start_non_stop (bool enable)
 544 {
 545   if (enable)
 546     return -1;
 547   else
 548     return 0;
 549 }
 550
 551 bool
 552 process_target::supports_multi_process ()
 553 {
 554   return false;
 555 }
 556
 557 bool
 558 process_target::supports_fork_events ()
 559 {
 560   return false;
 561 }
 562
 563 bool
 564 process_target::supports_vfork_events ()
 565 {
 566   return false;
 567 }
 568
 569 bool
 570 process_target::supports_exec_events ()
 571 {
 572   return false;
 573 }
 574
 575 void
 576 process_target::handle_new_gdb_connection ()
 577 {
 578   /* Nop.  */
 579 }
 580
 581 int
 582 process_target::handle_monitor_command (char *mon)
 583 {
 584   return 0;
 585 }
 586
 587 int
 588 process_target::core_of_thread (ptid_t ptid)
 589 {
 590   return -1;
 591 }
 592
 593 bool
 594 process_target::supports_read_loadmap ()
 595 {
 596   return false;
 597 }
 598
 599 int
 600 process_target::read_loadmap (const char *annex, CORE_ADDR offset,
 601                               unsigned char *myaddr, unsigned int len)
 602 {
 603   gdb_assert_not_reached ("target op read_loadmap not supported");
 604 }
 605
 606 void
 607 process_target::process_qsupported (char **features, int count)
 608 {
 609   /* Nop.  */
 610 }
 611
 612 bool
 613 process_target::supports_tracepoints ()
 614 {
 615   return false;
 616 }
 617
 618 CORE_ADDR
 619 process_target::read_pc (regcache *regcache)
 620 {
 621   gdb_assert_not_reached ("process_target::read_pc: Unable to find PC");
 622 }
 623
 624 void
 625 process_target::write_pc (regcache *regcache, CORE_ADDR pc)
 626 {
 627   gdb_assert_not_reached ("process_target::write_pc: Unable to update PC");
 628 }
 629
 630 bool
 631 process_target::supports_thread_stopped ()
 632 {
 633   return false;
 634 }
 635
 636 bool
 637 process_target::thread_stopped (thread_info *thread)
 638 {
 639   gdb_assert_not_reached ("target op thread_stopped not supported");
 640 }
 641
 642 bool
 643 process_target::supports_get_tib_address ()
 644 {
 645   return false;
 646 }
 647
 648 int
 649 process_target::get_tib_address (ptid_t ptid, CORE_ADDR *address)
 650 {
 651   gdb_assert_not_reached ("target op get_tib_address not supported");
 652 }