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->set_stopped (GDB_SIGNAL_0);
 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->exit_status ());
 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->sig ()),
 192                  gdb_signal_to_name (ourstatus->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 std::string
 280 target_pid_to_str (ptid_t ptid)
 281 {
 282   if (ptid == minus_one_ptid)
 283     return string_printf("<all threads>");
 284   else if (ptid == null_ptid)
 285     return string_printf("<null thread>");
 286   else if (ptid.tid () != 0)
 287     return string_printf("Thread %d.0x%s",
 288                          ptid.pid (),
 289                          phex_nz (ptid.tid (), sizeof (ULONGEST)));
 290   else if (ptid.lwp () != 0)
 291     return string_printf("LWP %d.%ld",
 292                          ptid.pid (), ptid.lwp ());
 293   else
 294     return string_printf("Process %d",
 295                          ptid.pid ());
 296 }
 297
 298 int
 299 kill_inferior (process_info *proc)
 300 {
 301   gdb_agent_about_to_close (proc->pid);
 302
 303   return the_target->kill (proc);
 304 }
 305
 306 /* Define it.  */
 307
 308 target_terminal_state target_terminal::m_terminal_state
 309   = target_terminal_state::is_ours;
 310
 311 /* See target/target.h.  */
 312
 313 void
 314 target_terminal::init ()
 315 {
 316   /* Placeholder needed because of fork_inferior.  Not necessary on
 317      GDBserver.  */
 318 }
 319
 320 /* See target/target.h.  */
 321
 322 void
 323 target_terminal::inferior ()
 324 {
 325   /* Placeholder needed because of fork_inferior.  Not necessary on
 326      GDBserver.  */
 327 }
 328
 329 /* See target/target.h.  */
 330
 331 void
 332 target_terminal::ours ()
 333 {
 334   /* Placeholder needed because of fork_inferior.  Not necessary on
 335      GDBserver.  */
 336 }
 337
 338 /* See target/target.h.  */
 339
 340 void
 341 target_terminal::ours_for_output (void)
 342 {
 343   /* Placeholder.  */
 344 }
 345
 346 /* See target/target.h.  */
 347
 348 void
 349 target_terminal::info (const char *arg, int from_tty)
 350 {
 351   /* Placeholder.  */
 352 }
 353
 354 /* Default implementations of target ops.
 355    See target.h for definitions.  */
 356
 357 void
 358 process_stratum_target::post_create_inferior ()
 359 {
 360   /* Nop.  */
 361 }
 362
 363 int
 364 process_stratum_target::prepare_to_access_memory ()
 365 {
 366   return 0;
 367 }
 368
 369 void
 370 process_stratum_target::done_accessing_memory ()
 371 {
 372   /* Nop.  */
 373 }
 374
 375 void
 376 process_stratum_target::look_up_symbols ()
 377 {
 378   /* Nop.  */
 379 }
 380
 381 bool
 382 process_stratum_target::supports_read_auxv ()
 383 {
 384   return false;
 385 }
 386
 387 int
 388 process_stratum_target::read_auxv (CORE_ADDR offset, unsigned char *myaddr,
 389                                    unsigned int len)
 390 {
 391   gdb_assert_not_reached ("target op read_auxv not supported");
 392 }
 393
 394 bool
 395 process_stratum_target::supports_z_point_type (char z_type)
 396 {
 397   return false;
 398 }
 399
 400 int
 401 process_stratum_target::insert_point (enum raw_bkpt_type type,
 402                                       CORE_ADDR addr,
 403                                       int size, raw_breakpoint *bp)
 404 {
 405   return 1;
 406 }
 407
 408 int
 409 process_stratum_target::remove_point (enum raw_bkpt_type type,
 410                                       CORE_ADDR addr,
 411                                       int size, raw_breakpoint *bp)
 412 {
 413   return 1;
 414 }
 415
 416 bool
 417 process_stratum_target::stopped_by_sw_breakpoint ()
 418 {
 419   return false;
 420 }
 421
 422 bool
 423 process_stratum_target::supports_stopped_by_sw_breakpoint ()
 424 {
 425   return false;
 426 }
 427
 428 bool
 429 process_stratum_target::stopped_by_hw_breakpoint ()
 430 {
 431   return false;
 432 }
 433
 434 bool
 435 process_stratum_target::supports_stopped_by_hw_breakpoint ()
 436 {
 437   return false;
 438 }
 439
 440 bool
 441 process_stratum_target::supports_hardware_single_step ()
 442 {
 443   return false;
 444 }
 445
 446 bool
 447 process_stratum_target::stopped_by_watchpoint ()
 448 {
 449   return false;
 450 }
 451
 452 CORE_ADDR
 453 process_stratum_target::stopped_data_address ()
 454 {
 455   return 0;
 456 }
 457
 458 bool
 459 process_stratum_target::supports_read_offsets ()
 460 {
 461   return false;
 462 }
 463
 464 bool
 465 process_stratum_target::supports_memory_tagging ()
 466 {
 467   return false;
 468 }
 469
 470 bool
 471 process_stratum_target::fetch_memtags (CORE_ADDR address, size_t len,
 472                                        gdb::byte_vector &tags, int type)
 473 {
 474   gdb_assert_not_reached ("target op fetch_memtags not supported");
 475 }
 476
 477 bool
 478 process_stratum_target::store_memtags (CORE_ADDR address, size_t len,
 479                                        const gdb::byte_vector &tags, int type)
 480 {
 481   gdb_assert_not_reached ("target op store_memtags not supported");
 482 }
 483
 484 int
 485 process_stratum_target::read_offsets (CORE_ADDR *text, CORE_ADDR *data)
 486 {
 487   gdb_assert_not_reached ("target op read_offsets not supported");
 488 }
 489
 490 bool
 491 process_stratum_target::supports_get_tls_address ()
 492 {
 493   return false;
 494 }
 495
 496 int
 497 process_stratum_target::get_tls_address (thread_info *thread,
 498                                          CORE_ADDR offset,
 499                                          CORE_ADDR load_module,
 500                                          CORE_ADDR *address)
 501 {
 502   gdb_assert_not_reached ("target op get_tls_address not supported");
 503 }
 504
 505 bool
 506 process_stratum_target::supports_qxfer_osdata ()
 507 {
 508   return false;
 509 }
 510
 511 int
 512 process_stratum_target::qxfer_osdata (const char *annex,
 513                                       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_stratum_target::supports_qxfer_siginfo ()
 522 {
 523   return false;
 524 }
 525
 526 int
 527 process_stratum_target::qxfer_siginfo (const char *annex,
 528                                        unsigned char *readbuf,
 529                                        unsigned const char *writebuf,
 530                                        CORE_ADDR offset, int len)
 531 {
 532   gdb_assert_not_reached ("target op qxfer_siginfo not supported");
 533 }
 534
 535 bool
 536 process_stratum_target::supports_non_stop ()
 537 {
 538   return false;
 539 }
 540
 541 bool
 542 process_stratum_target::async (bool enable)
 543 {
 544   return false;
 545 }
 546
 547 int
 548 process_stratum_target::start_non_stop (bool enable)
 549 {
 550   if (enable)
 551     return -1;
 552   else
 553     return 0;
 554 }
 555
 556 bool
 557 process_stratum_target::supports_multi_process ()
 558 {
 559   return false;
 560 }
 561
 562 bool
 563 process_stratum_target::supports_fork_events ()
 564 {
 565   return false;
 566 }
 567
 568 bool
 569 process_stratum_target::supports_vfork_events ()
 570 {
 571   return false;
 572 }
 573
 574 bool
 575 process_stratum_target::supports_exec_events ()
 576 {
 577   return false;
 578 }
 579
 580 void
 581 process_stratum_target::handle_new_gdb_connection ()
 582 {
 583   /* Nop.  */
 584 }
 585
 586 int
 587 process_stratum_target::handle_monitor_command (char *mon)
 588 {
 589   return 0;
 590 }
 591
 592 int
 593 process_stratum_target::core_of_thread (ptid_t ptid)
 594 {
 595   return -1;
 596 }
 597
 598 bool
 599 process_stratum_target::supports_read_loadmap ()
 600 {
 601   return false;
 602 }
 603
 604 int
 605 process_stratum_target::read_loadmap (const char *annex,
 606                                       CORE_ADDR offset,
 607                                       unsigned char *myaddr,
 608                                       unsigned int len)
 609 {
 610   gdb_assert_not_reached ("target op read_loadmap not supported");
 611 }
 612
 613 void
 614 process_stratum_target::process_qsupported
 615   (gdb::array_view<const char * const> features)
 616 {
 617   /* Nop.  */
 618 }
 619
 620 bool
 621 process_stratum_target::supports_tracepoints ()
 622 {
 623   return false;
 624 }
 625
 626 CORE_ADDR
 627 process_stratum_target::read_pc (regcache *regcache)
 628 {
 629   gdb_assert_not_reached ("process_target::read_pc: Unable to find PC");
 630 }
 631
 632 void
 633 process_stratum_target::write_pc (regcache *regcache, CORE_ADDR pc)
 634 {
 635   gdb_assert_not_reached ("process_target::write_pc: Unable to update PC");
 636 }
 637
 638 bool
 639 process_stratum_target::supports_thread_stopped ()
 640 {
 641   return false;
 642 }
 643
 644 bool
 645 process_stratum_target::thread_stopped (thread_info *thread)
 646 {
 647   gdb_assert_not_reached ("target op thread_stopped not supported");
 648 }
 649
 650 bool
 651 process_stratum_target::supports_get_tib_address ()
 652 {
 653   return false;
 654 }
 655
 656 int
 657 process_stratum_target::get_tib_address (ptid_t ptid, CORE_ADDR *address)
 658 {
 659   gdb_assert_not_reached ("target op get_tib_address not supported");
 660 }
 661
 662 void
 663 process_stratum_target::pause_all (bool freeze)
 664 {
 665   /* Nop.  */
 666 }
 667
 668 void
 669 process_stratum_target::unpause_all (bool unfreeze)
 670 {
 671   /* Nop.  */
 672 }
 673
 674 void
 675 process_stratum_target::stabilize_threads ()
 676 {
 677   /* Nop.  */
 678 }
 679
 680 bool
 681 process_stratum_target::supports_fast_tracepoints ()
 682 {
 683   return false;
 684 }
 685
 686 int
 687 process_stratum_target::install_fast_tracepoint_jump_pad
 688   (CORE_ADDR tpoint, CORE_ADDR tpaddr, CORE_ADDR collector,
 689    CORE_ADDR lockaddr, ULONGEST orig_size, CORE_ADDR *jump_entry,
 690    CORE_ADDR *trampoline, ULONGEST *trampoline_size,
 691    unsigned char *jjump_pad_insn, ULONGEST *jjump_pad_insn_size,
 692    CORE_ADDR *adjusted_insn_addr, CORE_ADDR *adjusted_insn_addr_end,
 693    char *err)
 694 {
 695   gdb_assert_not_reached ("target op install_fast_tracepoint_jump_pad "
 696                           "not supported");
 697 }
 698
 699 int
 700 process_stratum_target::get_min_fast_tracepoint_insn_len ()
 701 {
 702   return 0;
 703 }
 704
 705 struct emit_ops *
 706 process_stratum_target::emit_ops ()
 707 {
 708   return nullptr;
 709 }
 710
 711 bool
 712 process_stratum_target::supports_disable_randomization ()
 713 {
 714   return false;
 715 }
 716
 717 bool
 718 process_stratum_target::supports_qxfer_libraries_svr4 ()
 719 {
 720   return false;
 721 }
 722
 723 int
 724 process_stratum_target::qxfer_libraries_svr4 (const char *annex,
 725                                               unsigned char *readbuf,
 726                                               unsigned const char *writebuf,
 727                                               CORE_ADDR offset, int len)
 728 {
 729   gdb_assert_not_reached ("target op qxfer_libraries_svr4 not supported");
 730 }
 731
 732 bool
 733 process_stratum_target::supports_agent ()
 734 {
 735   return false;
 736 }
 737
 738 btrace_target_info *
 739 process_stratum_target::enable_btrace (ptid_t ptid, const btrace_config *conf)
 740 {
 741   error (_("Target does not support branch tracing."));
 742 }
 743
 744 int
 745 process_stratum_target::disable_btrace (btrace_target_info *tinfo)
 746 {
 747   error (_("Target does not support branch tracing."));
 748 }
 749
 750 int
 751 process_stratum_target::read_btrace (btrace_target_info *tinfo,
 752                              buffer *buffer,
 753                              enum btrace_read_type type)
 754 {
 755   error (_("Target does not support branch tracing."));
 756 }
 757
 758 int
 759 process_stratum_target::read_btrace_conf (const btrace_target_info *tinfo,
 760                                           buffer *buffer)
 761 {
 762   error (_("Target does not support branch tracing."));
 763 }
 764
 765 bool
 766 process_stratum_target::supports_range_stepping ()
 767 {
 768   return false;
 769 }
 770
 771 bool
 772 process_stratum_target::supports_pid_to_exec_file ()
 773 {
 774   return false;
 775 }
 776
 777 const char *
 778 process_stratum_target::pid_to_exec_file (int pid)
 779 {
 780   gdb_assert_not_reached ("target op pid_to_exec_file not supported");
 781 }
 782
 783 bool
 784 process_stratum_target::supports_multifs ()
 785 {
 786   return false;
 787 }
 788
 789 int
 790 process_stratum_target::multifs_open (int pid, const char *filename,
 791                                       int flags, mode_t mode)
 792 {
 793   return open (filename, flags, mode);
 794 }
 795
 796 int
 797 process_stratum_target::multifs_unlink (int pid, const char *filename)
 798 {
 799   return unlink (filename);
 800 }
 801
 802 ssize_t
 803 process_stratum_target::multifs_readlink (int pid, const char *filename,
 804                                           char *buf, size_t bufsiz)
 805 {
 806   return readlink (filename, buf, bufsiz);
 807 }
 808
 809 int
 810 process_stratum_target::breakpoint_kind_from_pc (CORE_ADDR *pcptr)
 811 {
 812   /* The default behavior is to use the size of a breakpoint as the
 813      kind.  */
 814   int size = 0;
 815   sw_breakpoint_from_kind (0, &size);
 816   return size;
 817 }
 818
 819 int
 820 process_stratum_target::breakpoint_kind_from_current_state (CORE_ADDR *pcptr)
 821 {
 822   return breakpoint_kind_from_pc (pcptr);
 823 }
 824
 825 const char *
 826 process_stratum_target::thread_name (ptid_t thread)
 827 {
 828   return nullptr;
 829 }
 830
 831 bool
 832 process_stratum_target::thread_handle (ptid_t ptid, gdb_byte **handle,
 833                                        int *handle_len)
 834 {
 835   return false;
 836 }
 837
 838 thread_info *
 839 process_stratum_target::thread_pending_parent (thread_info *thread)
 840 {
 841   return nullptr;
 842 }
 843
 844 thread_info *
 845 process_stratum_target::thread_pending_child (thread_info *thread)
 846 {
 847   return nullptr;
 848 }
 849
 850 bool
 851 process_stratum_target::supports_software_single_step ()
 852 {
 853   return false;
 854 }
 855
 856 bool
 857 process_stratum_target::supports_catch_syscall ()
 858 {
 859   return false;
 860 }
 861
 862 int
 863 process_stratum_target::get_ipa_tdesc_idx ()
 864 {
 865   return 0;
 866 }