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 #include <fcntl.h>
  26 #include <unistd.h>
  27 #include <sys/types.h>
  28 #include <sys/stat.h>
  29
  30 process_stratum_target *the_target;
  31
  32 int
  33 set_desired_thread ()
  34 {
  35   client_state &cs = get_client_state ();
  36   thread_info *found = find_thread_ptid (cs.general_thread);
  37
  38   current_thread = found;
  39   return (current_thread != NULL);
  40 }
  41
  42 /* The thread that was current before prepare_to_access_memory was
  43    called.  done_accessing_memory uses this to restore the previous
  44    selected thread.  */
  45 static ptid_t prev_general_thread;
  46
  47 /* See target.h.  */
  48
  49 int
  50 prepare_to_access_memory (void)
  51 {
  52   client_state &cs = get_client_state ();
  53
  54   /* The first thread found.  */
  55   struct thread_info *first = NULL;
  56   /* The first stopped thread found.  */
  57   struct thread_info *stopped = NULL;
  58   /* The current general thread, if found.  */
  59   struct thread_info *current = NULL;
  60
  61   /* Save the general thread value, since prepare_to_access_memory could change
  62      it.  */
  63   prev_general_thread = cs.general_thread;
  64
  65   int res = the_target->pt->prepare_to_access_memory ();
  66   if (res != 0)
  67     return res;
  68
  69   for_each_thread (prev_general_thread.pid (), [&] (thread_info *thread)
  70     {
  71       if (mythread_alive (thread->id))
  72         {
  73           if (stopped == NULL && the_target->pt->supports_thread_stopped ()
  74               && target_thread_stopped (thread))
  75             stopped = thread;
  76
  77           if (first == NULL)
  78             first = thread;
  79
  80           if (current == NULL && prev_general_thread == thread->id)
  81             current = thread;
  82         }
  83     });
  84
  85   /* The thread we end up choosing.  */
  86   struct thread_info *thread;
  87
  88   /* Prefer a stopped thread.  If none is found, try the current
  89      thread.  Otherwise, take the first thread in the process.  If
  90      none is found, undo the effects of
  91      target->prepare_to_access_memory() and return error.  */
  92   if (stopped != NULL)
  93     thread = stopped;
  94   else if (current != NULL)
  95     thread = current;
  96   else if (first != NULL)
  97     thread = first;
  98   else
  99     {
 100       done_accessing_memory ();
 101       return 1;
 102     }
 103
 104   current_thread = thread;
 105   cs.general_thread = ptid_of (thread);
 106
 107   return 0;
 108 }
 109
 110 /* See target.h.  */
 111
 112 void
 113 done_accessing_memory (void)
 114 {
 115   client_state &cs = get_client_state ();
 116
 117   the_target->pt->done_accessing_memory ();
 118
 119   /* Restore the previous selected thread.  */
 120   cs.general_thread = prev_general_thread;
 121   switch_to_thread (the_target, cs.general_thread);
 122 }
 123
 124 int
 125 read_inferior_memory (CORE_ADDR memaddr, unsigned char *myaddr, int len)
 126 {
 127   int res;
 128   res = the_target->pt->read_memory (memaddr, myaddr, len);
 129   check_mem_read (memaddr, myaddr, len);
 130   return res;
 131 }
 132
 133 /* See target/target.h.  */
 134
 135 int
 136 target_read_memory (CORE_ADDR memaddr, gdb_byte *myaddr, ssize_t len)
 137 {
 138   return read_inferior_memory (memaddr, myaddr, len);
 139 }
 140
 141 /* See target/target.h.  */
 142
 143 int
 144 target_read_uint32 (CORE_ADDR memaddr, uint32_t *result)
 145 {
 146   return read_inferior_memory (memaddr, (gdb_byte *) result, sizeof (*result));
 147 }
 148
 149 /* See target/target.h.  */
 150
 151 int
 152 target_write_memory (CORE_ADDR memaddr, const unsigned char *myaddr,
 153                      ssize_t len)
 154 {
 155   /* Make a copy of the data because check_mem_write may need to
 156      update it.  */
 157   gdb::byte_vector buffer (myaddr, myaddr + len);
 158   check_mem_write (memaddr, buffer.data (), myaddr, len);
 159   return the_target->pt->write_memory (memaddr, buffer.data (), len);
 160 }
 161
 162 ptid_t
 163 mywait (ptid_t ptid, struct target_waitstatus *ourstatus, int options,
 164         int connected_wait)
 165 {
 166   ptid_t ret;
 167
 168   if (connected_wait)
 169     server_waiting = 1;
 170
 171   ret = target_wait (ptid, ourstatus, options);
 172
 173   /* We don't expose _LOADED events to gdbserver core.  See the
 174      `dlls_changed' global.  */
 175   if (ourstatus->kind == TARGET_WAITKIND_LOADED)
 176     ourstatus->kind = TARGET_WAITKIND_STOPPED;
 177
 178   /* If GDB is connected through TCP/serial, then GDBserver will most
 179      probably be running on its own terminal/console, so it's nice to
 180      print there why is GDBserver exiting.  If however, GDB is
 181      connected through stdio, then there's no need to spam the GDB
 182      console with this -- the user will already see the exit through
 183      regular GDB output, in that same terminal.  */
 184   if (!remote_connection_is_stdio ())
 185     {
 186       if (ourstatus->kind == TARGET_WAITKIND_EXITED)
 187         fprintf (stderr,
 188                  "\nChild exited with status %d\n", ourstatus->value.integer);
 189       else if (ourstatus->kind == TARGET_WAITKIND_SIGNALLED)
 190         fprintf (stderr, "\nChild terminated with signal = 0x%x (%s)\n",
 191                  gdb_signal_to_host (ourstatus->value.sig),
 192                  gdb_signal_to_name (ourstatus->value.sig));
 193     }
 194
 195   if (connected_wait)
 196     server_waiting = 0;
 197
 198   return ret;
 199 }
 200
 201 /* See target/target.h.  */
 202
 203 void
 204 target_stop_and_wait (ptid_t ptid)
 205 {
 206   struct target_waitstatus status;
 207   bool was_non_stop = non_stop;
 208   struct thread_resume resume_info;
 209
 210   resume_info.thread = ptid;
 211   resume_info.kind = resume_stop;
 212   resume_info.sig = GDB_SIGNAL_0;
 213   the_target->pt->resume (&resume_info, 1);
 214
 215   non_stop = true;
 216   mywait (ptid, &status, 0, 0);
 217   non_stop = was_non_stop;
 218 }
 219
 220 /* See target/target.h.  */
 221
 222 ptid_t
 223 target_wait (ptid_t ptid, struct target_waitstatus *status, int options)
 224 {
 225   return the_target->pt->wait (ptid, status, options);
 226 }
 227
 228 /* See target/target.h.  */
 229
 230 void
 231 target_mourn_inferior (ptid_t ptid)
 232 {
 233   the_target->pt->mourn (find_process_pid (ptid.pid ()));
 234 }
 235
 236 /* See target/target.h.  */
 237
 238 void
 239 target_continue_no_signal (ptid_t ptid)
 240 {
 241   struct thread_resume resume_info;
 242
 243   resume_info.thread = ptid;
 244   resume_info.kind = resume_continue;
 245   resume_info.sig = GDB_SIGNAL_0;
 246   the_target->pt->resume (&resume_info, 1);
 247 }
 248
 249 /* See target/target.h.  */
 250
 251 void
 252 target_continue (ptid_t ptid, enum gdb_signal signal)
 253 {
 254   struct thread_resume resume_info;
 255
 256   resume_info.thread = ptid;
 257   resume_info.kind = resume_continue;
 258   resume_info.sig = gdb_signal_to_host (signal);
 259   the_target->pt->resume (&resume_info, 1);
 260 }
 261
 262 /* See target/target.h.  */
 263
 264 int
 265 target_supports_multi_process (void)
 266 {
 267   return the_target->pt->supports_multi_process ();
 268 }
 269
 270 void
 271 set_target_ops (process_stratum_target *target)
 272 {
 273   the_target = XNEW (process_stratum_target);
 274   memcpy (the_target, target, sizeof (*the_target));
 275 }
 276
 277 /* Convert pid to printable format.  */
 278
 279 const char *
 280 target_pid_to_str (ptid_t ptid)
 281 {
 282   static char buf[80];
 283
 284   if (ptid == minus_one_ptid)
 285     xsnprintf (buf, sizeof (buf), "<all threads>");
 286   else if (ptid == null_ptid)
 287     xsnprintf (buf, sizeof (buf), "<null thread>");
 288   else if (ptid.tid () != 0)
 289     xsnprintf (buf, sizeof (buf), "Thread %d.0x%lx",
 290                ptid.pid (), ptid.tid ());
 291   else if (ptid.lwp () != 0)
 292     xsnprintf (buf, sizeof (buf), "LWP %d.%ld",
 293                ptid.pid (), ptid.lwp ());
 294   else
 295     xsnprintf (buf, sizeof (buf), "Process %d",
 296                ptid.pid ());
 297
 298   return buf;
 299 }
 300
 301 int
 302 kill_inferior (process_info *proc)
 303 {
 304   gdb_agent_about_to_close (proc->pid);
 305
 306   return the_target->pt->kill (proc);
 307 }
 308
 309 /* Default implementation for breakpoint_kind_for_pc.
 310
 311    The default behavior for targets that don't implement breakpoint_kind_for_pc
 312    is to use the size of a breakpoint as the kind.  */
 313
 314 int
 315 default_breakpoint_kind_from_pc (CORE_ADDR *pcptr)
 316 {
 317   int size = 0;
 318
 319   gdb_assert (the_target->sw_breakpoint_from_kind != NULL);
 320
 321   (*the_target->sw_breakpoint_from_kind) (0, &size);
 322   return size;
 323 }
 324
 325 /* Define it.  */
 326
 327 target_terminal_state target_terminal::m_terminal_state
 328   = target_terminal_state::is_ours;
 329
 330 /* See target/target.h.  */
 331
 332 void
 333 target_terminal::init ()
 334 {
 335   /* Placeholder needed because of fork_inferior.  Not necessary on
 336      GDBserver.  */
 337 }
 338
 339 /* See target/target.h.  */
 340
 341 void
 342 target_terminal::inferior ()
 343 {
 344   /* Placeholder needed because of fork_inferior.  Not necessary on
 345      GDBserver.  */
 346 }
 347
 348 /* See target/target.h.  */
 349
 350 void
 351 target_terminal::ours ()
 352 {
 353   /* Placeholder needed because of fork_inferior.  Not necessary on
 354      GDBserver.  */
 355 }
 356
 357 /* See target/target.h.  */
 358
 359 void
 360 target_terminal::ours_for_output (void)
 361 {
 362   /* Placeholder.  */
 363 }
 364
 365 /* See target/target.h.  */
 366
 367 void
 368 target_terminal::info (const char *arg, int from_tty)
 369 {
 370   /* Placeholder.  */
 371 }
 372
 373 /* Default implementations of target ops.
 374    See target.h for definitions.  */
 375
 376 void
 377 process_target::post_create_inferior ()
 378 {
 379   /* Nop.  */
 380 }
 381
 382 int
 383 process_target::prepare_to_access_memory ()
 384 {
 385   return 0;
 386 }
 387
 388 void
 389 process_target::done_accessing_memory ()
 390 {
 391   /* Nop.  */
 392 }
 393
 394 void
 395 process_target::look_up_symbols ()
 396 {
 397   /* Nop.  */
 398 }
 399
 400 bool
 401 process_target::supports_read_auxv ()
 402 {
 403   return false;
 404 }
 405
 406 int
 407 process_target::read_auxv (CORE_ADDR offset, unsigned char *myaddr,
 408                            unsigned int len)
 409 {
 410   gdb_assert_not_reached ("target op read_auxv not supported");
 411 }
 412
 413 bool
 414 process_target::supports_z_point_type (char z_type)
 415 {
 416   return false;
 417 }
 418
 419 int
 420 process_target::insert_point (enum raw_bkpt_type type, CORE_ADDR addr,
 421                               int size, raw_breakpoint *bp)
 422 {
 423   return 1;
 424 }
 425
 426 int
 427 process_target::remove_point (enum raw_bkpt_type type, CORE_ADDR addr,
 428                               int size, raw_breakpoint *bp)
 429 {
 430   return 1;
 431 }
 432
 433 bool
 434 process_target::stopped_by_sw_breakpoint ()
 435 {
 436   return false;
 437 }
 438
 439 bool
 440 process_target::supports_stopped_by_sw_breakpoint ()
 441 {
 442   return false;
 443 }
 444
 445 bool
 446 process_target::stopped_by_hw_breakpoint ()
 447 {
 448   return false;
 449 }
 450
 451 bool
 452 process_target::supports_stopped_by_hw_breakpoint ()
 453 {
 454   return false;
 455 }
 456
 457 bool
 458 process_target::supports_hardware_single_step ()
 459 {
 460   return false;
 461 }
 462
 463 bool
 464 process_target::stopped_by_watchpoint ()
 465 {
 466   return false;
 467 }
 468
 469 CORE_ADDR
 470 process_target::stopped_data_address ()
 471 {
 472   return 0;
 473 }
 474
 475 bool
 476 process_target::supports_read_offsets ()
 477 {
 478   return false;
 479 }
 480
 481 int
 482 process_target::read_offsets (CORE_ADDR *text, CORE_ADDR *data)
 483 {
 484   gdb_assert_not_reached ("target op read_offsets not supported");
 485 }
 486
 487 bool
 488 process_target::supports_get_tls_address ()
 489 {
 490   return false;
 491 }
 492
 493 int
 494 process_target::get_tls_address (thread_info *thread, CORE_ADDR offset,
 495                                  CORE_ADDR load_module, CORE_ADDR *address)
 496 {
 497   gdb_assert_not_reached ("target op get_tls_address not supported");
 498 }
 499
 500 void
 501 process_target::hostio_last_error (char *buf)
 502 {
 503   hostio_last_error_from_errno (buf);
 504 }
 505
 506 bool
 507 process_target::supports_qxfer_osdata ()
 508 {
 509   return false;
 510 }
 511
 512 int
 513 process_target::qxfer_osdata (const char *annex, unsigned char *readbuf,
 514                               unsigned const char *writebuf,
 515                               CORE_ADDR offset, int len)
 516 {
 517   gdb_assert_not_reached ("target op qxfer_osdata not supported");
 518 }
 519
 520 bool
 521 process_target::supports_qxfer_siginfo ()
 522 {
 523   return false;
 524 }
 525
 526 int
 527 process_target::qxfer_siginfo (const char *annex, unsigned char *readbuf,
 528                                unsigned const char *writebuf,
 529                                CORE_ADDR offset, int len)
 530 {
 531   gdb_assert_not_reached ("target op qxfer_siginfo not supported");
 532 }
 533
 534 bool
 535 process_target::supports_non_stop ()
 536 {
 537   return false;
 538 }
 539
 540 bool
 541 process_target::async (bool enable)
 542 {
 543   return false;
 544 }
 545
 546 int
 547 process_target::start_non_stop (bool enable)
 548 {
 549   if (enable)
 550     return -1;
 551   else
 552     return 0;
 553 }
 554
 555 bool
 556 process_target::supports_multi_process ()
 557 {
 558   return false;
 559 }
 560
 561 bool
 562 process_target::supports_fork_events ()
 563 {
 564   return false;
 565 }
 566
 567 bool
 568 process_target::supports_vfork_events ()
 569 {
 570   return false;
 571 }
 572
 573 bool
 574 process_target::supports_exec_events ()
 575 {
 576   return false;
 577 }
 578
 579 void
 580 process_target::handle_new_gdb_connection ()
 581 {
 582   /* Nop.  */
 583 }
 584
 585 int
 586 process_target::handle_monitor_command (char *mon)
 587 {
 588   return 0;
 589 }
 590
 591 int
 592 process_target::core_of_thread (ptid_t ptid)
 593 {
 594   return -1;
 595 }
 596
 597 bool
 598 process_target::supports_read_loadmap ()
 599 {
 600   return false;
 601 }
 602
 603 int
 604 process_target::read_loadmap (const char *annex, CORE_ADDR offset,
 605                               unsigned char *myaddr, unsigned int len)
 606 {
 607   gdb_assert_not_reached ("target op read_loadmap not supported");
 608 }
 609
 610 void
 611 process_target::process_qsupported (char **features, int count)
 612 {
 613   /* Nop.  */
 614 }
 615
 616 bool
 617 process_target::supports_tracepoints ()
 618 {
 619   return false;
 620 }
 621
 622 CORE_ADDR
 623 process_target::read_pc (regcache *regcache)
 624 {
 625   gdb_assert_not_reached ("process_target::read_pc: Unable to find PC");
 626 }
 627
 628 void
 629 process_target::write_pc (regcache *regcache, CORE_ADDR pc)
 630 {
 631   gdb_assert_not_reached ("process_target::write_pc: Unable to update PC");
 632 }
 633
 634 bool
 635 process_target::supports_thread_stopped ()
 636 {
 637   return false;
 638 }
 639
 640 bool
 641 process_target::thread_stopped (thread_info *thread)
 642 {
 643   gdb_assert_not_reached ("target op thread_stopped not supported");
 644 }
 645
 646 bool
 647 process_target::supports_get_tib_address ()
 648 {
 649   return false;
 650 }
 651
 652 int
 653 process_target::get_tib_address (ptid_t ptid, CORE_ADDR *address)
 654 {
 655   gdb_assert_not_reached ("target op get_tib_address not supported");
 656 }
 657
 658 void
 659 process_target::pause_all (bool freeze)
 660 {
 661   /* Nop.  */
 662 }
 663
 664 void
 665 process_target::unpause_all (bool unfreeze)
 666 {
 667   /* Nop.  */
 668 }
 669
 670 void
 671 process_target::stabilize_threads ()
 672 {
 673   /* Nop.  */
 674 }
 675
 676 bool
 677 process_target::supports_fast_tracepoints ()
 678 {
 679   return false;
 680 }
 681
 682 int
 683 process_target::install_fast_tracepoint_jump_pad
 684   (CORE_ADDR tpoint, CORE_ADDR tpaddr, CORE_ADDR collector,
 685    CORE_ADDR lockaddr, ULONGEST orig_size, CORE_ADDR *jump_entry,
 686    CORE_ADDR *trampoline, ULONGEST *trampoline_size,
 687    unsigned char *jjump_pad_insn, ULONGEST *jjump_pad_insn_size,
 688    CORE_ADDR *adjusted_insn_addr, CORE_ADDR *adjusted_insn_addr_end,
 689    char *err)
 690 {
 691   gdb_assert_not_reached ("target op install_fast_tracepoint_jump_pad "
 692                           "not supported");
 693 }
 694
 695 int
 696 process_target::get_min_fast_tracepoint_insn_len ()
 697 {
 698   return 0;
 699 }
 700
 701 struct emit_ops *
 702 process_target::emit_ops ()
 703 {
 704   return nullptr;
 705 }
 706
 707 bool
 708 process_target::supports_disable_randomization ()
 709 {
 710   return false;
 711 }
 712
 713 bool
 714 process_target::supports_qxfer_libraries_svr4 ()
 715 {
 716   return false;
 717 }
 718
 719 int
 720 process_target::qxfer_libraries_svr4 (const char *annex,
 721                                       unsigned char *readbuf,
 722                                       unsigned const char *writebuf,
 723                                       CORE_ADDR offset, int len)
 724 {
 725   gdb_assert_not_reached ("target op qxfer_libraries_svr4 not supported");
 726 }
 727
 728 bool
 729 process_target::supports_agent ()
 730 {
 731   return false;
 732 }
 733
 734 btrace_target_info *
 735 process_target::enable_btrace (ptid_t ptid, const btrace_config *conf)
 736 {
 737   error (_("Target does not support branch tracing."));
 738 }
 739
 740 int
 741 process_target::disable_btrace (btrace_target_info *tinfo)
 742 {
 743   error (_("Target does not support branch tracing."));
 744 }
 745
 746 int
 747 process_target::read_btrace (btrace_target_info *tinfo,
 748                              buffer *buffer,
 749                              enum btrace_read_type type)
 750 {
 751   error (_("Target does not support branch tracing."));
 752 }
 753
 754 int
 755 process_target::read_btrace_conf (const btrace_target_info *tinfo,
 756                                   buffer *buffer)
 757 {
 758   error (_("Target does not support branch tracing."));
 759 }
 760
 761 bool
 762 process_target::supports_range_stepping ()
 763 {
 764   return false;
 765 }
 766
 767 bool
 768 process_target::supports_pid_to_exec_file ()
 769 {
 770   return false;
 771 }
 772
 773 char *
 774 process_target::pid_to_exec_file (int pid)
 775 {
 776   gdb_assert_not_reached ("target op pid_to_exec_file not supported");
 777 }
 778
 779 bool
 780 process_target::supports_multifs ()
 781 {
 782   return false;
 783 }
 784
 785 int
 786 process_target::multifs_open (int pid, const char *filename,
 787                               int flags, mode_t mode)
 788 {
 789   return open (filename, flags, mode);
 790 }
 791
 792 int
 793 process_target::multifs_unlink (int pid, const char *filename)
 794 {
 795   return unlink (filename);
 796 }
 797
 798 ssize_t
 799 process_target::multifs_readlink (int pid, const char *filename,
 800                                   char *buf, size_t bufsiz)
 801 {
 802   return readlink (filename, buf, bufsiz);
 803 }