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 = target;
 274 }
 275
 276 /* Convert pid to printable format.  */
 277
 278 const char *
 279 target_pid_to_str (ptid_t ptid)
 280 {
 281   static char buf[80];
 282
 283   if (ptid == minus_one_ptid)
 284     xsnprintf (buf, sizeof (buf), "<all threads>");
 285   else if (ptid == null_ptid)
 286     xsnprintf (buf, sizeof (buf), "<null thread>");
 287   else if (ptid.tid () != 0)
 288     xsnprintf (buf, sizeof (buf), "Thread %d.0x%lx",
 289                ptid.pid (), ptid.tid ());
 290   else if (ptid.lwp () != 0)
 291     xsnprintf (buf, sizeof (buf), "LWP %d.%ld",
 292                ptid.pid (), ptid.lwp ());
 293   else
 294     xsnprintf (buf, sizeof (buf), "Process %d",
 295                ptid.pid ());
 296
 297   return buf;
 298 }
 299
 300 int
 301 kill_inferior (process_info *proc)
 302 {
 303   gdb_agent_about_to_close (proc->pid);
 304
 305   return the_target->pt->kill (proc);
 306 }
 307
 308 /* Define it.  */
 309
 310 target_terminal_state target_terminal::m_terminal_state
 311   = target_terminal_state::is_ours;
 312
 313 /* See target/target.h.  */
 314
 315 void
 316 target_terminal::init ()
 317 {
 318   /* Placeholder needed because of fork_inferior.  Not necessary on
 319      GDBserver.  */
 320 }
 321
 322 /* See target/target.h.  */
 323
 324 void
 325 target_terminal::inferior ()
 326 {
 327   /* Placeholder needed because of fork_inferior.  Not necessary on
 328      GDBserver.  */
 329 }
 330
 331 /* See target/target.h.  */
 332
 333 void
 334 target_terminal::ours ()
 335 {
 336   /* Placeholder needed because of fork_inferior.  Not necessary on
 337      GDBserver.  */
 338 }
 339
 340 /* See target/target.h.  */
 341
 342 void
 343 target_terminal::ours_for_output (void)
 344 {
 345   /* Placeholder.  */
 346 }
 347
 348 /* See target/target.h.  */
 349
 350 void
 351 target_terminal::info (const char *arg, int from_tty)
 352 {
 353   /* Placeholder.  */
 354 }
 355
 356 /* Default implementations of target ops.
 357    See target.h for definitions.  */
 358
 359 void
 360 process_target::post_create_inferior ()
 361 {
 362   /* Nop.  */
 363 }
 364
 365 int
 366 process_target::prepare_to_access_memory ()
 367 {
 368   return 0;
 369 }
 370
 371 void
 372 process_target::done_accessing_memory ()
 373 {
 374   /* Nop.  */
 375 }
 376
 377 void
 378 process_target::look_up_symbols ()
 379 {
 380   /* Nop.  */
 381 }
 382
 383 bool
 384 process_target::supports_read_auxv ()
 385 {
 386   return false;
 387 }
 388
 389 int
 390 process_target::read_auxv (CORE_ADDR offset, unsigned char *myaddr,
 391                            unsigned int len)
 392 {
 393   gdb_assert_not_reached ("target op read_auxv not supported");
 394 }
 395
 396 bool
 397 process_target::supports_z_point_type (char z_type)
 398 {
 399   return false;
 400 }
 401
 402 int
 403 process_target::insert_point (enum raw_bkpt_type type, CORE_ADDR addr,
 404                               int size, raw_breakpoint *bp)
 405 {
 406   return 1;
 407 }
 408
 409 int
 410 process_target::remove_point (enum raw_bkpt_type type, CORE_ADDR addr,
 411                               int size, raw_breakpoint *bp)
 412 {
 413   return 1;
 414 }
 415
 416 bool
 417 process_target::stopped_by_sw_breakpoint ()
 418 {
 419   return false;
 420 }
 421
 422 bool
 423 process_target::supports_stopped_by_sw_breakpoint ()
 424 {
 425   return false;
 426 }
 427
 428 bool
 429 process_target::stopped_by_hw_breakpoint ()
 430 {
 431   return false;
 432 }
 433
 434 bool
 435 process_target::supports_stopped_by_hw_breakpoint ()
 436 {
 437   return false;
 438 }
 439
 440 bool
 441 process_target::supports_hardware_single_step ()
 442 {
 443   return false;
 444 }
 445
 446 bool
 447 process_target::stopped_by_watchpoint ()
 448 {
 449   return false;
 450 }
 451
 452 CORE_ADDR
 453 process_target::stopped_data_address ()
 454 {
 455   return 0;
 456 }
 457
 458 bool
 459 process_target::supports_read_offsets ()
 460 {
 461   return false;
 462 }
 463
 464 int
 465 process_target::read_offsets (CORE_ADDR *text, CORE_ADDR *data)
 466 {
 467   gdb_assert_not_reached ("target op read_offsets not supported");
 468 }
 469
 470 bool
 471 process_target::supports_get_tls_address ()
 472 {
 473   return false;
 474 }
 475
 476 int
 477 process_target::get_tls_address (thread_info *thread, CORE_ADDR offset,
 478                                  CORE_ADDR load_module, CORE_ADDR *address)
 479 {
 480   gdb_assert_not_reached ("target op get_tls_address not supported");
 481 }
 482
 483 void
 484 process_target::hostio_last_error (char *buf)
 485 {
 486   hostio_last_error_from_errno (buf);
 487 }
 488
 489 bool
 490 process_target::supports_qxfer_osdata ()
 491 {
 492   return false;
 493 }
 494
 495 int
 496 process_target::qxfer_osdata (const char *annex, unsigned char *readbuf,
 497                               unsigned const char *writebuf,
 498                               CORE_ADDR offset, int len)
 499 {
 500   gdb_assert_not_reached ("target op qxfer_osdata not supported");
 501 }
 502
 503 bool
 504 process_target::supports_qxfer_siginfo ()
 505 {
 506   return false;
 507 }
 508
 509 int
 510 process_target::qxfer_siginfo (const char *annex, unsigned char *readbuf,
 511                                unsigned const char *writebuf,
 512                                CORE_ADDR offset, int len)
 513 {
 514   gdb_assert_not_reached ("target op qxfer_siginfo not supported");
 515 }
 516
 517 bool
 518 process_target::supports_non_stop ()
 519 {
 520   return false;
 521 }
 522
 523 bool
 524 process_target::async (bool enable)
 525 {
 526   return false;
 527 }
 528
 529 int
 530 process_target::start_non_stop (bool enable)
 531 {
 532   if (enable)
 533     return -1;
 534   else
 535     return 0;
 536 }
 537
 538 bool
 539 process_target::supports_multi_process ()
 540 {
 541   return false;
 542 }
 543
 544 bool
 545 process_target::supports_fork_events ()
 546 {
 547   return false;
 548 }
 549
 550 bool
 551 process_target::supports_vfork_events ()
 552 {
 553   return false;
 554 }
 555
 556 bool
 557 process_target::supports_exec_events ()
 558 {
 559   return false;
 560 }
 561
 562 void
 563 process_target::handle_new_gdb_connection ()
 564 {
 565   /* Nop.  */
 566 }
 567
 568 int
 569 process_target::handle_monitor_command (char *mon)
 570 {
 571   return 0;
 572 }
 573
 574 int
 575 process_target::core_of_thread (ptid_t ptid)
 576 {
 577   return -1;
 578 }
 579
 580 bool
 581 process_target::supports_read_loadmap ()
 582 {
 583   return false;
 584 }
 585
 586 int
 587 process_target::read_loadmap (const char *annex, CORE_ADDR offset,
 588                               unsigned char *myaddr, unsigned int len)
 589 {
 590   gdb_assert_not_reached ("target op read_loadmap not supported");
 591 }
 592
 593 void
 594 process_target::process_qsupported (char **features, int count)
 595 {
 596   /* Nop.  */
 597 }
 598
 599 bool
 600 process_target::supports_tracepoints ()
 601 {
 602   return false;
 603 }
 604
 605 CORE_ADDR
 606 process_target::read_pc (regcache *regcache)
 607 {
 608   gdb_assert_not_reached ("process_target::read_pc: Unable to find PC");
 609 }
 610
 611 void
 612 process_target::write_pc (regcache *regcache, CORE_ADDR pc)
 613 {
 614   gdb_assert_not_reached ("process_target::write_pc: Unable to update PC");
 615 }
 616
 617 bool
 618 process_target::supports_thread_stopped ()
 619 {
 620   return false;
 621 }
 622
 623 bool
 624 process_target::thread_stopped (thread_info *thread)
 625 {
 626   gdb_assert_not_reached ("target op thread_stopped not supported");
 627 }
 628
 629 bool
 630 process_target::supports_get_tib_address ()
 631 {
 632   return false;
 633 }
 634
 635 int
 636 process_target::get_tib_address (ptid_t ptid, CORE_ADDR *address)
 637 {
 638   gdb_assert_not_reached ("target op get_tib_address not supported");
 639 }
 640
 641 void
 642 process_target::pause_all (bool freeze)
 643 {
 644   /* Nop.  */
 645 }
 646
 647 void
 648 process_target::unpause_all (bool unfreeze)
 649 {
 650   /* Nop.  */
 651 }
 652
 653 void
 654 process_target::stabilize_threads ()
 655 {
 656   /* Nop.  */
 657 }
 658
 659 bool
 660 process_target::supports_fast_tracepoints ()
 661 {
 662   return false;
 663 }
 664
 665 int
 666 process_target::install_fast_tracepoint_jump_pad
 667   (CORE_ADDR tpoint, CORE_ADDR tpaddr, CORE_ADDR collector,
 668    CORE_ADDR lockaddr, ULONGEST orig_size, CORE_ADDR *jump_entry,
 669    CORE_ADDR *trampoline, ULONGEST *trampoline_size,
 670    unsigned char *jjump_pad_insn, ULONGEST *jjump_pad_insn_size,
 671    CORE_ADDR *adjusted_insn_addr, CORE_ADDR *adjusted_insn_addr_end,
 672    char *err)
 673 {
 674   gdb_assert_not_reached ("target op install_fast_tracepoint_jump_pad "
 675                           "not supported");
 676 }
 677
 678 int
 679 process_target::get_min_fast_tracepoint_insn_len ()
 680 {
 681   return 0;
 682 }
 683
 684 struct emit_ops *
 685 process_target::emit_ops ()
 686 {
 687   return nullptr;
 688 }
 689
 690 bool
 691 process_target::supports_disable_randomization ()
 692 {
 693   return false;
 694 }
 695
 696 bool
 697 process_target::supports_qxfer_libraries_svr4 ()
 698 {
 699   return false;
 700 }
 701
 702 int
 703 process_target::qxfer_libraries_svr4 (const char *annex,
 704                                       unsigned char *readbuf,
 705                                       unsigned const char *writebuf,
 706                                       CORE_ADDR offset, int len)
 707 {
 708   gdb_assert_not_reached ("target op qxfer_libraries_svr4 not supported");
 709 }
 710
 711 bool
 712 process_target::supports_agent ()
 713 {
 714   return false;
 715 }
 716
 717 btrace_target_info *
 718 process_target::enable_btrace (ptid_t ptid, const btrace_config *conf)
 719 {
 720   error (_("Target does not support branch tracing."));
 721 }
 722
 723 int
 724 process_target::disable_btrace (btrace_target_info *tinfo)
 725 {
 726   error (_("Target does not support branch tracing."));
 727 }
 728
 729 int
 730 process_target::read_btrace (btrace_target_info *tinfo,
 731                              buffer *buffer,
 732                              enum btrace_read_type type)
 733 {
 734   error (_("Target does not support branch tracing."));
 735 }
 736
 737 int
 738 process_target::read_btrace_conf (const btrace_target_info *tinfo,
 739                                   buffer *buffer)
 740 {
 741   error (_("Target does not support branch tracing."));
 742 }
 743
 744 bool
 745 process_target::supports_range_stepping ()
 746 {
 747   return false;
 748 }
 749
 750 bool
 751 process_target::supports_pid_to_exec_file ()
 752 {
 753   return false;
 754 }
 755
 756 char *
 757 process_target::pid_to_exec_file (int pid)
 758 {
 759   gdb_assert_not_reached ("target op pid_to_exec_file not supported");
 760 }
 761
 762 bool
 763 process_target::supports_multifs ()
 764 {
 765   return false;
 766 }
 767
 768 int
 769 process_target::multifs_open (int pid, const char *filename,
 770                               int flags, mode_t mode)
 771 {
 772   return open (filename, flags, mode);
 773 }
 774
 775 int
 776 process_target::multifs_unlink (int pid, const char *filename)
 777 {
 778   return unlink (filename);
 779 }
 780
 781 ssize_t
 782 process_target::multifs_readlink (int pid, const char *filename,
 783                                   char *buf, size_t bufsiz)
 784 {
 785   return readlink (filename, buf, bufsiz);
 786 }
 787
 788 int
 789 process_target::breakpoint_kind_from_pc (CORE_ADDR *pcptr)
 790 {
 791   /* The default behavior is to use the size of a breakpoint as the
 792      kind.  */
 793   int size = 0;
 794   sw_breakpoint_from_kind (0, &size);
 795   return size;
 796 }
 797
 798 int
 799 process_target::breakpoint_kind_from_current_state (CORE_ADDR *pcptr)
 800 {
 801   return breakpoint_kind_from_pc (pcptr);
 802 }
 803
 804 const char *
 805 process_target::thread_name (ptid_t thread)
 806 {
 807   return nullptr;
 808 }
 809
 810 bool
 811 process_target::thread_handle (ptid_t ptid, gdb_byte **handle,
 812                                int *handle_len)
 813 {
 814   return false;
 815 }
 816
 817 bool
 818 process_target::supports_software_single_step ()
 819 {
 820   return false;
 821 }
 822
 823 bool
 824 process_target::supports_catch_syscall ()
 825 {
 826   return false;
 827 }
 828
 829 int
 830 process_target::get_ipa_tdesc_idx ()
 831 {
 832   return 0;
 833 }