gdbserver/target.cc

   1 /* Target operations for the remote server for GDB.
   2    Copyright (C) 2002-2021 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->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->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->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->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->write_memory (memaddr, buffer.data (), len);
 160 }
 161
 162 ptid_t
 163 mywait (ptid_t ptid, struct target_waitstatus *ourstatus,
 164         target_wait_flags options, 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->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,
 224              target_wait_flags options)
 225 {
 226   return the_target->wait (ptid, status, options);
 227 }
 228
 229 /* See target/target.h.  */
 230
 231 void
 232 target_mourn_inferior (ptid_t ptid)
 233 {
 234   the_target->mourn (find_process_pid (ptid.pid ()));
 235 }
 236
 237 /* See target/target.h.  */
 238
 239 void
 240 target_continue_no_signal (ptid_t ptid)
 241 {
 242   struct thread_resume resume_info;
 243
 244   resume_info.thread = ptid;
 245   resume_info.kind = resume_continue;
 246   resume_info.sig = GDB_SIGNAL_0;
 247   the_target->resume (&resume_info, 1);
 248 }
 249
 250 /* See target/target.h.  */
 251
 252 void
 253 target_continue (ptid_t ptid, enum gdb_signal signal)
 254 {
 255   struct thread_resume resume_info;
 256
 257   resume_info.thread = ptid;
 258   resume_info.kind = resume_continue;
 259   resume_info.sig = gdb_signal_to_host (signal);
 260   the_target->resume (&resume_info, 1);
 261 }
 262
 263 /* See target/target.h.  */
 264
 265 int
 266 target_supports_multi_process (void)
 267 {
 268   return the_target->supports_multi_process ();
 269 }
 270
 271 void
 272 set_target_ops (process_stratum_target *target)
 273 {
 274   the_target = 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->kill (proc);
 307 }
 308
 309 /* Define it.  */
 310
 311 target_terminal_state target_terminal::m_terminal_state
 312   = target_terminal_state::is_ours;
 313
 314 /* See target/target.h.  */
 315
 316 void
 317 target_terminal::init ()
 318 {
 319   /* Placeholder needed because of fork_inferior.  Not necessary on
 320      GDBserver.  */
 321 }
 322
 323 /* See target/target.h.  */
 324
 325 void
 326 target_terminal::inferior ()
 327 {
 328   /* Placeholder needed because of fork_inferior.  Not necessary on
 329      GDBserver.  */
 330 }
 331
 332 /* See target/target.h.  */
 333
 334 void
 335 target_terminal::ours ()
 336 {
 337   /* Placeholder needed because of fork_inferior.  Not necessary on
 338      GDBserver.  */
 339 }
 340
 341 /* See target/target.h.  */
 342
 343 void
 344 target_terminal::ours_for_output (void)
 345 {
 346   /* Placeholder.  */
 347 }
 348
 349 /* See target/target.h.  */
 350
 351 void
 352 target_terminal::info (const char *arg, int from_tty)
 353 {
 354   /* Placeholder.  */
 355 }
 356
 357 /* Default implementations of target ops.
 358    See target.h for definitions.  */
 359
 360 void
 361 process_stratum_target::post_create_inferior ()
 362 {
 363   /* Nop.  */
 364 }
 365
 366 int
 367 process_stratum_target::prepare_to_access_memory ()
 368 {
 369   return 0;
 370 }
 371
 372 void
 373 process_stratum_target::done_accessing_memory ()
 374 {
 375   /* Nop.  */
 376 }
 377
 378 void
 379 process_stratum_target::look_up_symbols ()
 380 {
 381   /* Nop.  */
 382 }
 383
 384 bool
 385 process_stratum_target::supports_read_auxv ()
 386 {
 387   return false;
 388 }
 389
 390 int
 391 process_stratum_target::read_auxv (CORE_ADDR offset, unsigned char *myaddr,
 392                                    unsigned int len)
 393 {
 394   gdb_assert_not_reached ("target op read_auxv not supported");
 395 }
 396
 397 bool
 398 process_stratum_target::supports_z_point_type (char z_type)
 399 {
 400   return false;
 401 }
 402
 403 int
 404 process_stratum_target::insert_point (enum raw_bkpt_type type,
 405                                       CORE_ADDR addr,
 406                                       int size, raw_breakpoint *bp)
 407 {
 408   return 1;
 409 }
 410
 411 int
 412 process_stratum_target::remove_point (enum raw_bkpt_type type,
 413                                       CORE_ADDR addr,
 414                                       int size, raw_breakpoint *bp)
 415 {
 416   return 1;
 417 }
 418
 419 bool
 420 process_stratum_target::stopped_by_sw_breakpoint ()
 421 {
 422   return false;
 423 }
 424
 425 bool
 426 process_stratum_target::supports_stopped_by_sw_breakpoint ()
 427 {
 428   return false;
 429 }
 430
 431 bool
 432 process_stratum_target::stopped_by_hw_breakpoint ()
 433 {
 434   return false;
 435 }
 436
 437 bool
 438 process_stratum_target::supports_stopped_by_hw_breakpoint ()
 439 {
 440   return false;
 441 }
 442
 443 bool
 444 process_stratum_target::supports_hardware_single_step ()
 445 {
 446   return false;
 447 }
 448
 449 bool
 450 process_stratum_target::stopped_by_watchpoint ()
 451 {
 452   return false;
 453 }
 454
 455 CORE_ADDR
 456 process_stratum_target::stopped_data_address ()
 457 {
 458   return 0;
 459 }
 460
 461 bool
 462 process_stratum_target::supports_read_offsets ()
 463 {
 464   return false;
 465 }
 466
 467 bool
 468 process_stratum_target::supports_memory_tagging ()
 469 {
 470   return false;
 471 }
 472
 473 bool
 474 process_stratum_target::fetch_memtags (CORE_ADDR address, size_t len,
 475                                        gdb::byte_vector &tags, int type)
 476 {
 477   gdb_assert_not_reached ("target op fetch_memtags not supported");
 478 }
 479
 480 bool
 481 process_stratum_target::store_memtags (CORE_ADDR address, size_t len,
 482                                        const gdb::byte_vector &tags, int type)
 483 {
 484   gdb_assert_not_reached ("target op store_memtags not supported");
 485 }
 486
 487 int
 488 process_stratum_target::read_offsets (CORE_ADDR *text, CORE_ADDR *data)
 489 {
 490   gdb_assert_not_reached ("target op read_offsets not supported");
 491 }
 492
 493 bool
 494 process_stratum_target::supports_get_tls_address ()
 495 {
 496   return false;
 497 }
 498
 499 int
 500 process_stratum_target::get_tls_address (thread_info *thread,
 501                                          CORE_ADDR offset,
 502                                          CORE_ADDR load_module,
 503                                          CORE_ADDR *address)
 504 {
 505   gdb_assert_not_reached ("target op get_tls_address not supported");
 506 }
 507
 508 bool
 509 process_stratum_target::supports_qxfer_osdata ()
 510 {
 511   return false;
 512 }
 513
 514 int
 515 process_stratum_target::qxfer_osdata (const char *annex,
 516                                       unsigned char *readbuf,
 517                                       unsigned const char *writebuf,
 518                                       CORE_ADDR offset, int len)
 519 {
 520   gdb_assert_not_reached ("target op qxfer_osdata not supported");
 521 }
 522
 523 bool
 524 process_stratum_target::supports_qxfer_siginfo ()
 525 {
 526   return false;
 527 }
 528
 529 int
 530 process_stratum_target::qxfer_siginfo (const char *annex,
 531                                        unsigned char *readbuf,
 532                                        unsigned const char *writebuf,
 533                                        CORE_ADDR offset, int len)
 534 {
 535   gdb_assert_not_reached ("target op qxfer_siginfo not supported");
 536 }
 537
 538 bool
 539 process_stratum_target::supports_non_stop ()
 540 {
 541   return false;
 542 }
 543
 544 bool
 545 process_stratum_target::async (bool enable)
 546 {
 547   return false;
 548 }
 549
 550 int
 551 process_stratum_target::start_non_stop (bool enable)
 552 {
 553   if (enable)
 554     return -1;
 555   else
 556     return 0;
 557 }
 558
 559 bool
 560 process_stratum_target::supports_multi_process ()
 561 {
 562   return false;
 563 }
 564
 565 bool
 566 process_stratum_target::supports_fork_events ()
 567 {
 568   return false;
 569 }
 570
 571 bool
 572 process_stratum_target::supports_vfork_events ()
 573 {
 574   return false;
 575 }
 576
 577 bool
 578 process_stratum_target::supports_exec_events ()
 579 {
 580   return false;
 581 }
 582
 583 void
 584 process_stratum_target::handle_new_gdb_connection ()
 585 {
 586   /* Nop.  */
 587 }
 588
 589 int
 590 process_stratum_target::handle_monitor_command (char *mon)
 591 {
 592   return 0;
 593 }
 594
 595 int
 596 process_stratum_target::core_of_thread (ptid_t ptid)
 597 {
 598   return -1;
 599 }
 600
 601 bool
 602 process_stratum_target::supports_read_loadmap ()
 603 {
 604   return false;
 605 }
 606
 607 int
 608 process_stratum_target::read_loadmap (const char *annex,
 609                                       CORE_ADDR offset,
 610                                       unsigned char *myaddr,
 611                                       unsigned int len)
 612 {
 613   gdb_assert_not_reached ("target op read_loadmap not supported");
 614 }
 615
 616 void
 617 process_stratum_target::process_qsupported
 618   (gdb::array_view<const char * const> features)
 619 {
 620   /* Nop.  */
 621 }
 622
 623 bool
 624 process_stratum_target::supports_tracepoints ()
 625 {
 626   return false;
 627 }
 628
 629 CORE_ADDR
 630 process_stratum_target::read_pc (regcache *regcache)
 631 {
 632   gdb_assert_not_reached ("process_target::read_pc: Unable to find PC");
 633 }
 634
 635 void
 636 process_stratum_target::write_pc (regcache *regcache, CORE_ADDR pc)
 637 {
 638   gdb_assert_not_reached ("process_target::write_pc: Unable to update PC");
 639 }
 640
 641 bool
 642 process_stratum_target::supports_thread_stopped ()
 643 {
 644   return false;
 645 }
 646
 647 bool
 648 process_stratum_target::thread_stopped (thread_info *thread)
 649 {
 650   gdb_assert_not_reached ("target op thread_stopped not supported");
 651 }
 652
 653 bool
 654 process_stratum_target::supports_get_tib_address ()
 655 {
 656   return false;
 657 }
 658
 659 int
 660 process_stratum_target::get_tib_address (ptid_t ptid, CORE_ADDR *address)
 661 {
 662   gdb_assert_not_reached ("target op get_tib_address not supported");
 663 }
 664
 665 void
 666 process_stratum_target::pause_all (bool freeze)
 667 {
 668   /* Nop.  */
 669 }
 670
 671 void
 672 process_stratum_target::unpause_all (bool unfreeze)
 673 {
 674   /* Nop.  */
 675 }
 676
 677 void
 678 process_stratum_target::stabilize_threads ()
 679 {
 680   /* Nop.  */
 681 }
 682
 683 bool
 684 process_stratum_target::supports_fast_tracepoints ()
 685 {
 686   return false;
 687 }
 688
 689 int
 690 process_stratum_target::install_fast_tracepoint_jump_pad
 691   (CORE_ADDR tpoint, CORE_ADDR tpaddr, CORE_ADDR collector,
 692    CORE_ADDR lockaddr, ULONGEST orig_size, CORE_ADDR *jump_entry,
 693    CORE_ADDR *trampoline, ULONGEST *trampoline_size,
 694    unsigned char *jjump_pad_insn, ULONGEST *jjump_pad_insn_size,
 695    CORE_ADDR *adjusted_insn_addr, CORE_ADDR *adjusted_insn_addr_end,
 696    char *err)
 697 {
 698   gdb_assert_not_reached ("target op install_fast_tracepoint_jump_pad "
 699                           "not supported");
 700 }
 701
 702 int
 703 process_stratum_target::get_min_fast_tracepoint_insn_len ()
 704 {
 705   return 0;
 706 }
 707
 708 struct emit_ops *
 709 process_stratum_target::emit_ops ()
 710 {
 711   return nullptr;
 712 }
 713
 714 bool
 715 process_stratum_target::supports_disable_randomization ()
 716 {
 717   return false;
 718 }
 719
 720 bool
 721 process_stratum_target::supports_qxfer_libraries_svr4 ()
 722 {
 723   return false;
 724 }
 725
 726 int
 727 process_stratum_target::qxfer_libraries_svr4 (const char *annex,
 728                                               unsigned char *readbuf,
 729                                               unsigned const char *writebuf,
 730                                               CORE_ADDR offset, int len)
 731 {
 732   gdb_assert_not_reached ("target op qxfer_libraries_svr4 not supported");
 733 }
 734
 735 bool
 736 process_stratum_target::supports_agent ()
 737 {
 738   return false;
 739 }
 740
 741 btrace_target_info *
 742 process_stratum_target::enable_btrace (ptid_t ptid, const btrace_config *conf)
 743 {
 744   error (_("Target does not support branch tracing."));
 745 }
 746
 747 int
 748 process_stratum_target::disable_btrace (btrace_target_info *tinfo)
 749 {
 750   error (_("Target does not support branch tracing."));
 751 }
 752
 753 int
 754 process_stratum_target::read_btrace (btrace_target_info *tinfo,
 755                              buffer *buffer,
 756                              enum btrace_read_type type)
 757 {
 758   error (_("Target does not support branch tracing."));
 759 }
 760
 761 int
 762 process_stratum_target::read_btrace_conf (const btrace_target_info *tinfo,
 763                                           buffer *buffer)
 764 {
 765   error (_("Target does not support branch tracing."));
 766 }
 767
 768 bool
 769 process_stratum_target::supports_range_stepping ()
 770 {
 771   return false;
 772 }
 773
 774 bool
 775 process_stratum_target::supports_pid_to_exec_file ()
 776 {
 777   return false;
 778 }
 779
 780 const char *
 781 process_stratum_target::pid_to_exec_file (int pid)
 782 {
 783   gdb_assert_not_reached ("target op pid_to_exec_file not supported");
 784 }
 785
 786 bool
 787 process_stratum_target::supports_multifs ()
 788 {
 789   return false;
 790 }
 791
 792 int
 793 process_stratum_target::multifs_open (int pid, const char *filename,
 794                                       int flags, mode_t mode)
 795 {
 796   return open (filename, flags, mode);
 797 }
 798
 799 int
 800 process_stratum_target::multifs_unlink (int pid, const char *filename)
 801 {
 802   return unlink (filename);
 803 }
 804
 805 ssize_t
 806 process_stratum_target::multifs_readlink (int pid, const char *filename,
 807                                           char *buf, size_t bufsiz)
 808 {
 809   return readlink (filename, buf, bufsiz);
 810 }
 811
 812 int
 813 process_stratum_target::breakpoint_kind_from_pc (CORE_ADDR *pcptr)
 814 {
 815   /* The default behavior is to use the size of a breakpoint as the
 816      kind.  */
 817   int size = 0;
 818   sw_breakpoint_from_kind (0, &size);
 819   return size;
 820 }
 821
 822 int
 823 process_stratum_target::breakpoint_kind_from_current_state (CORE_ADDR *pcptr)
 824 {
 825   return breakpoint_kind_from_pc (pcptr);
 826 }
 827
 828 const char *
 829 process_stratum_target::thread_name (ptid_t thread)
 830 {
 831   return nullptr;
 832 }
 833
 834 bool
 835 process_stratum_target::thread_handle (ptid_t ptid, gdb_byte **handle,
 836                                        int *handle_len)
 837 {
 838   return false;
 839 }
 840
 841 bool
 842 process_stratum_target::supports_software_single_step ()
 843 {
 844   return false;
 845 }
 846
 847 bool
 848 process_stratum_target::supports_catch_syscall ()
 849 {
 850   return false;
 851 }
 852
 853 int
 854 process_stratum_target::get_ipa_tdesc_idx ()
 855 {
 856   return 0;
 857 }