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->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 int
 468 process_stratum_target::read_offsets (CORE_ADDR *text, CORE_ADDR *data)
 469 {
 470   gdb_assert_not_reached ("target op read_offsets not supported");
 471 }
 472
 473 bool
 474 process_stratum_target::supports_get_tls_address ()
 475 {
 476   return false;
 477 }
 478
 479 int
 480 process_stratum_target::get_tls_address (thread_info *thread,
 481                                          CORE_ADDR offset,
 482                                          CORE_ADDR load_module,
 483                                          CORE_ADDR *address)
 484 {
 485   gdb_assert_not_reached ("target op get_tls_address not supported");
 486 }
 487
 488 void
 489 process_stratum_target::hostio_last_error (char *buf)
 490 {
 491   hostio_last_error_from_errno (buf);
 492 }
 493
 494 bool
 495 process_stratum_target::supports_qxfer_osdata ()
 496 {
 497   return false;
 498 }
 499
 500 int
 501 process_stratum_target::qxfer_osdata (const char *annex,
 502                                       unsigned char *readbuf,
 503                                       unsigned const char *writebuf,
 504                                       CORE_ADDR offset, int len)
 505 {
 506   gdb_assert_not_reached ("target op qxfer_osdata not supported");
 507 }
 508
 509 bool
 510 process_stratum_target::supports_qxfer_siginfo ()
 511 {
 512   return false;
 513 }
 514
 515 int
 516 process_stratum_target::qxfer_siginfo (const char *annex,
 517                                        unsigned char *readbuf,
 518                                        unsigned const char *writebuf,
 519                                        CORE_ADDR offset, int len)
 520 {
 521   gdb_assert_not_reached ("target op qxfer_siginfo not supported");
 522 }
 523
 524 bool
 525 process_stratum_target::supports_non_stop ()
 526 {
 527   return false;
 528 }
 529
 530 bool
 531 process_stratum_target::async (bool enable)
 532 {
 533   return false;
 534 }
 535
 536 int
 537 process_stratum_target::start_non_stop (bool enable)
 538 {
 539   if (enable)
 540     return -1;
 541   else
 542     return 0;
 543 }
 544
 545 bool
 546 process_stratum_target::supports_multi_process ()
 547 {
 548   return false;
 549 }
 550
 551 bool
 552 process_stratum_target::supports_fork_events ()
 553 {
 554   return false;
 555 }
 556
 557 bool
 558 process_stratum_target::supports_vfork_events ()
 559 {
 560   return false;
 561 }
 562
 563 bool
 564 process_stratum_target::supports_exec_events ()
 565 {
 566   return false;
 567 }
 568
 569 void
 570 process_stratum_target::handle_new_gdb_connection ()
 571 {
 572   /* Nop.  */
 573 }
 574
 575 int
 576 process_stratum_target::handle_monitor_command (char *mon)
 577 {
 578   return 0;
 579 }
 580
 581 int
 582 process_stratum_target::core_of_thread (ptid_t ptid)
 583 {
 584   return -1;
 585 }
 586
 587 bool
 588 process_stratum_target::supports_read_loadmap ()
 589 {
 590   return false;
 591 }
 592
 593 int
 594 process_stratum_target::read_loadmap (const char *annex,
 595                                       CORE_ADDR offset,
 596                                       unsigned char *myaddr,
 597                                       unsigned int len)
 598 {
 599   gdb_assert_not_reached ("target op read_loadmap not supported");
 600 }
 601
 602 void
 603 process_stratum_target::process_qsupported
 604   (gdb::array_view<const char * const> features)
 605 {
 606   /* Nop.  */
 607 }
 608
 609 bool
 610 process_stratum_target::supports_tracepoints ()
 611 {
 612   return false;
 613 }
 614
 615 CORE_ADDR
 616 process_stratum_target::read_pc (regcache *regcache)
 617 {
 618   gdb_assert_not_reached ("process_target::read_pc: Unable to find PC");
 619 }
 620
 621 void
 622 process_stratum_target::write_pc (regcache *regcache, CORE_ADDR pc)
 623 {
 624   gdb_assert_not_reached ("process_target::write_pc: Unable to update PC");
 625 }
 626
 627 bool
 628 process_stratum_target::supports_thread_stopped ()
 629 {
 630   return false;
 631 }
 632
 633 bool
 634 process_stratum_target::thread_stopped (thread_info *thread)
 635 {
 636   gdb_assert_not_reached ("target op thread_stopped not supported");
 637 }
 638
 639 bool
 640 process_stratum_target::supports_get_tib_address ()
 641 {
 642   return false;
 643 }
 644
 645 int
 646 process_stratum_target::get_tib_address (ptid_t ptid, CORE_ADDR *address)
 647 {
 648   gdb_assert_not_reached ("target op get_tib_address not supported");
 649 }
 650
 651 void
 652 process_stratum_target::pause_all (bool freeze)
 653 {
 654   /* Nop.  */
 655 }
 656
 657 void
 658 process_stratum_target::unpause_all (bool unfreeze)
 659 {
 660   /* Nop.  */
 661 }
 662
 663 void
 664 process_stratum_target::stabilize_threads ()
 665 {
 666   /* Nop.  */
 667 }
 668
 669 bool
 670 process_stratum_target::supports_fast_tracepoints ()
 671 {
 672   return false;
 673 }
 674
 675 int
 676 process_stratum_target::install_fast_tracepoint_jump_pad
 677   (CORE_ADDR tpoint, CORE_ADDR tpaddr, CORE_ADDR collector,
 678    CORE_ADDR lockaddr, ULONGEST orig_size, CORE_ADDR *jump_entry,
 679    CORE_ADDR *trampoline, ULONGEST *trampoline_size,
 680    unsigned char *jjump_pad_insn, ULONGEST *jjump_pad_insn_size,
 681    CORE_ADDR *adjusted_insn_addr, CORE_ADDR *adjusted_insn_addr_end,
 682    char *err)
 683 {
 684   gdb_assert_not_reached ("target op install_fast_tracepoint_jump_pad "
 685                           "not supported");
 686 }
 687
 688 int
 689 process_stratum_target::get_min_fast_tracepoint_insn_len ()
 690 {
 691   return 0;
 692 }
 693
 694 struct emit_ops *
 695 process_stratum_target::emit_ops ()
 696 {
 697   return nullptr;
 698 }
 699
 700 bool
 701 process_stratum_target::supports_disable_randomization ()
 702 {
 703   return false;
 704 }
 705
 706 bool
 707 process_stratum_target::supports_qxfer_libraries_svr4 ()
 708 {
 709   return false;
 710 }
 711
 712 int
 713 process_stratum_target::qxfer_libraries_svr4 (const char *annex,
 714                                               unsigned char *readbuf,
 715                                               unsigned const char *writebuf,
 716                                               CORE_ADDR offset, int len)
 717 {
 718   gdb_assert_not_reached ("target op qxfer_libraries_svr4 not supported");
 719 }
 720
 721 bool
 722 process_stratum_target::supports_agent ()
 723 {
 724   return false;
 725 }
 726
 727 btrace_target_info *
 728 process_stratum_target::enable_btrace (ptid_t ptid, const btrace_config *conf)
 729 {
 730   error (_("Target does not support branch tracing."));
 731 }
 732
 733 int
 734 process_stratum_target::disable_btrace (btrace_target_info *tinfo)
 735 {
 736   error (_("Target does not support branch tracing."));
 737 }
 738
 739 int
 740 process_stratum_target::read_btrace (btrace_target_info *tinfo,
 741                              buffer *buffer,
 742                              enum btrace_read_type type)
 743 {
 744   error (_("Target does not support branch tracing."));
 745 }
 746
 747 int
 748 process_stratum_target::read_btrace_conf (const btrace_target_info *tinfo,
 749                                           buffer *buffer)
 750 {
 751   error (_("Target does not support branch tracing."));
 752 }
 753
 754 bool
 755 process_stratum_target::supports_range_stepping ()
 756 {
 757   return false;
 758 }
 759
 760 bool
 761 process_stratum_target::supports_pid_to_exec_file ()
 762 {
 763   return false;
 764 }
 765
 766 char *
 767 process_stratum_target::pid_to_exec_file (int pid)
 768 {
 769   gdb_assert_not_reached ("target op pid_to_exec_file not supported");
 770 }
 771
 772 bool
 773 process_stratum_target::supports_multifs ()
 774 {
 775   return false;
 776 }
 777
 778 int
 779 process_stratum_target::multifs_open (int pid, const char *filename,
 780                                       int flags, mode_t mode)
 781 {
 782   return open (filename, flags, mode);
 783 }
 784
 785 int
 786 process_stratum_target::multifs_unlink (int pid, const char *filename)
 787 {
 788   return unlink (filename);
 789 }
 790
 791 ssize_t
 792 process_stratum_target::multifs_readlink (int pid, const char *filename,
 793                                           char *buf, size_t bufsiz)
 794 {
 795   return readlink (filename, buf, bufsiz);
 796 }
 797
 798 int
 799 process_stratum_target::breakpoint_kind_from_pc (CORE_ADDR *pcptr)
 800 {
 801   /* The default behavior is to use the size of a breakpoint as the
 802      kind.  */
 803   int size = 0;
 804   sw_breakpoint_from_kind (0, &size);
 805   return size;
 806 }
 807
 808 int
 809 process_stratum_target::breakpoint_kind_from_current_state (CORE_ADDR *pcptr)
 810 {
 811   return breakpoint_kind_from_pc (pcptr);
 812 }
 813
 814 const char *
 815 process_stratum_target::thread_name (ptid_t thread)
 816 {
 817   return nullptr;
 818 }
 819
 820 bool
 821 process_stratum_target::thread_handle (ptid_t ptid, gdb_byte **handle,
 822                                        int *handle_len)
 823 {
 824   return false;
 825 }
 826
 827 bool
 828 process_stratum_target::supports_software_single_step ()
 829 {
 830   return false;
 831 }
 832
 833 bool
 834 process_stratum_target::supports_catch_syscall ()
 835 {
 836   return false;
 837 }
 838
 839 int
 840 process_stratum_target::get_ipa_tdesc_idx ()
 841 {
 842   return 0;
 843 }