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 /* 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_target::post_create_inferior ()
 362 {
 363   /* Nop.  */
 364 }
 365
 366 int
 367 process_target::prepare_to_access_memory ()
 368 {
 369   return 0;
 370 }
 371
 372 void
 373 process_target::done_accessing_memory ()
 374 {
 375   /* Nop.  */
 376 }
 377
 378 void
 379 process_target::look_up_symbols ()
 380 {
 381   /* Nop.  */
 382 }
 383
 384 bool
 385 process_target::supports_read_auxv ()
 386 {
 387   return false;
 388 }
 389
 390 int
 391 process_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_target::supports_z_point_type (char z_type)
 399 {
 400   return false;
 401 }
 402
 403 int
 404 process_target::insert_point (enum raw_bkpt_type type, CORE_ADDR addr,
 405                               int size, raw_breakpoint *bp)
 406 {
 407   return 1;
 408 }
 409
 410 int
 411 process_target::remove_point (enum raw_bkpt_type type, CORE_ADDR addr,
 412                               int size, raw_breakpoint *bp)
 413 {
 414   return 1;
 415 }
 416
 417 bool
 418 process_target::stopped_by_sw_breakpoint ()
 419 {
 420   return false;
 421 }
 422
 423 bool
 424 process_target::supports_stopped_by_sw_breakpoint ()
 425 {
 426   return false;
 427 }
 428
 429 bool
 430 process_target::stopped_by_hw_breakpoint ()
 431 {
 432   return false;
 433 }
 434
 435 bool
 436 process_target::supports_stopped_by_hw_breakpoint ()
 437 {
 438   return false;
 439 }
 440
 441 bool
 442 process_target::supports_hardware_single_step ()
 443 {
 444   return false;
 445 }
 446
 447 bool
 448 process_target::stopped_by_watchpoint ()
 449 {
 450   return false;
 451 }
 452
 453 CORE_ADDR
 454 process_target::stopped_data_address ()
 455 {
 456   return 0;
 457 }
 458
 459 bool
 460 process_target::supports_read_offsets ()
 461 {
 462   return false;
 463 }
 464
 465 int
 466 process_target::read_offsets (CORE_ADDR *text, CORE_ADDR *data)
 467 {
 468   gdb_assert_not_reached ("target op read_offsets not supported");
 469 }
 470
 471 bool
 472 process_target::supports_get_tls_address ()
 473 {
 474   return false;
 475 }
 476
 477 int
 478 process_target::get_tls_address (thread_info *thread, CORE_ADDR offset,
 479                                  CORE_ADDR load_module, CORE_ADDR *address)
 480 {
 481   gdb_assert_not_reached ("target op get_tls_address not supported");
 482 }
 483
 484 void
 485 process_target::hostio_last_error (char *buf)
 486 {
 487   hostio_last_error_from_errno (buf);
 488 }
 489
 490 bool
 491 process_target::supports_qxfer_osdata ()
 492 {
 493   return false;
 494 }
 495
 496 int
 497 process_target::qxfer_osdata (const char *annex, unsigned char *readbuf,
 498                               unsigned const char *writebuf,
 499                               CORE_ADDR offset, int len)
 500 {
 501   gdb_assert_not_reached ("target op qxfer_osdata not supported");
 502 }
 503
 504 bool
 505 process_target::supports_qxfer_siginfo ()
 506 {
 507   return false;
 508 }
 509
 510 int
 511 process_target::qxfer_siginfo (const char *annex, unsigned char *readbuf,
 512                                unsigned const char *writebuf,
 513                                CORE_ADDR offset, int len)
 514 {
 515   gdb_assert_not_reached ("target op qxfer_siginfo not supported");
 516 }
 517
 518 bool
 519 process_target::supports_non_stop ()
 520 {
 521   return false;
 522 }
 523
 524 bool
 525 process_target::async (bool enable)
 526 {
 527   return false;
 528 }
 529
 530 int
 531 process_target::start_non_stop (bool enable)
 532 {
 533   if (enable)
 534     return -1;
 535   else
 536     return 0;
 537 }
 538
 539 bool
 540 process_target::supports_multi_process ()
 541 {
 542   return false;
 543 }
 544
 545 bool
 546 process_target::supports_fork_events ()
 547 {
 548   return false;
 549 }
 550
 551 bool
 552 process_target::supports_vfork_events ()
 553 {
 554   return false;
 555 }
 556
 557 bool
 558 process_target::supports_exec_events ()
 559 {
 560   return false;
 561 }
 562
 563 void
 564 process_target::handle_new_gdb_connection ()
 565 {
 566   /* Nop.  */
 567 }
 568
 569 int
 570 process_target::handle_monitor_command (char *mon)
 571 {
 572   return 0;
 573 }
 574
 575 int
 576 process_target::core_of_thread (ptid_t ptid)
 577 {
 578   return -1;
 579 }
 580
 581 bool
 582 process_target::supports_read_loadmap ()
 583 {
 584   return false;
 585 }
 586
 587 int
 588 process_target::read_loadmap (const char *annex, CORE_ADDR offset,
 589                               unsigned char *myaddr, unsigned int len)
 590 {
 591   gdb_assert_not_reached ("target op read_loadmap not supported");
 592 }
 593
 594 void
 595 process_target::process_qsupported (char **features, int count)
 596 {
 597   /* Nop.  */
 598 }
 599
 600 bool
 601 process_target::supports_tracepoints ()
 602 {
 603   return false;
 604 }
 605
 606 CORE_ADDR
 607 process_target::read_pc (regcache *regcache)
 608 {
 609   gdb_assert_not_reached ("process_target::read_pc: Unable to find PC");
 610 }
 611
 612 void
 613 process_target::write_pc (regcache *regcache, CORE_ADDR pc)
 614 {
 615   gdb_assert_not_reached ("process_target::write_pc: Unable to update PC");
 616 }
 617
 618 bool
 619 process_target::supports_thread_stopped ()
 620 {
 621   return false;
 622 }
 623
 624 bool
 625 process_target::thread_stopped (thread_info *thread)
 626 {
 627   gdb_assert_not_reached ("target op thread_stopped not supported");
 628 }
 629
 630 bool
 631 process_target::supports_get_tib_address ()
 632 {
 633   return false;
 634 }
 635
 636 int
 637 process_target::get_tib_address (ptid_t ptid, CORE_ADDR *address)
 638 {
 639   gdb_assert_not_reached ("target op get_tib_address not supported");
 640 }
 641
 642 void
 643 process_target::pause_all (bool freeze)
 644 {
 645   /* Nop.  */
 646 }
 647
 648 void
 649 process_target::unpause_all (bool unfreeze)
 650 {
 651   /* Nop.  */
 652 }
 653
 654 void
 655 process_target::stabilize_threads ()
 656 {
 657   /* Nop.  */
 658 }
 659
 660 bool
 661 process_target::supports_fast_tracepoints ()
 662 {
 663   return false;
 664 }
 665
 666 int
 667 process_target::install_fast_tracepoint_jump_pad
 668   (CORE_ADDR tpoint, CORE_ADDR tpaddr, CORE_ADDR collector,
 669    CORE_ADDR lockaddr, ULONGEST orig_size, CORE_ADDR *jump_entry,
 670    CORE_ADDR *trampoline, ULONGEST *trampoline_size,
 671    unsigned char *jjump_pad_insn, ULONGEST *jjump_pad_insn_size,
 672    CORE_ADDR *adjusted_insn_addr, CORE_ADDR *adjusted_insn_addr_end,
 673    char *err)
 674 {
 675   gdb_assert_not_reached ("target op install_fast_tracepoint_jump_pad "
 676                           "not supported");
 677 }
 678
 679 int
 680 process_target::get_min_fast_tracepoint_insn_len ()
 681 {
 682   return 0;
 683 }
 684
 685 struct emit_ops *
 686 process_target::emit_ops ()
 687 {
 688   return nullptr;
 689 }
 690
 691 bool
 692 process_target::supports_disable_randomization ()
 693 {
 694   return false;
 695 }
 696
 697 bool
 698 process_target::supports_qxfer_libraries_svr4 ()
 699 {
 700   return false;
 701 }
 702
 703 int
 704 process_target::qxfer_libraries_svr4 (const char *annex,
 705                                       unsigned char *readbuf,
 706                                       unsigned const char *writebuf,
 707                                       CORE_ADDR offset, int len)
 708 {
 709   gdb_assert_not_reached ("target op qxfer_libraries_svr4 not supported");
 710 }
 711
 712 bool
 713 process_target::supports_agent ()
 714 {
 715   return false;
 716 }
 717
 718 btrace_target_info *
 719 process_target::enable_btrace (ptid_t ptid, const btrace_config *conf)
 720 {
 721   error (_("Target does not support branch tracing."));
 722 }
 723
 724 int
 725 process_target::disable_btrace (btrace_target_info *tinfo)
 726 {
 727   error (_("Target does not support branch tracing."));
 728 }
 729
 730 int
 731 process_target::read_btrace (btrace_target_info *tinfo,
 732                              buffer *buffer,
 733                              enum btrace_read_type type)
 734 {
 735   error (_("Target does not support branch tracing."));
 736 }
 737
 738 int
 739 process_target::read_btrace_conf (const btrace_target_info *tinfo,
 740                                   buffer *buffer)
 741 {
 742   error (_("Target does not support branch tracing."));
 743 }
 744
 745 bool
 746 process_target::supports_range_stepping ()
 747 {
 748   return false;
 749 }
 750
 751 bool
 752 process_target::supports_pid_to_exec_file ()
 753 {
 754   return false;
 755 }
 756
 757 char *
 758 process_target::pid_to_exec_file (int pid)
 759 {
 760   gdb_assert_not_reached ("target op pid_to_exec_file not supported");
 761 }
 762
 763 bool
 764 process_target::supports_multifs ()
 765 {
 766   return false;
 767 }
 768
 769 int
 770 process_target::multifs_open (int pid, const char *filename,
 771                               int flags, mode_t mode)
 772 {
 773   return open (filename, flags, mode);
 774 }
 775
 776 int
 777 process_target::multifs_unlink (int pid, const char *filename)
 778 {
 779   return unlink (filename);
 780 }
 781
 782 ssize_t
 783 process_target::multifs_readlink (int pid, const char *filename,
 784                                   char *buf, size_t bufsiz)
 785 {
 786   return readlink (filename, buf, bufsiz);
 787 }
 788
 789 int
 790 process_target::breakpoint_kind_from_pc (CORE_ADDR *pcptr)
 791 {
 792   /* The default behavior is to use the size of a breakpoint as the
 793      kind.  */
 794   int size = 0;
 795   sw_breakpoint_from_kind (0, &size);
 796   return size;
 797 }
 798
 799 int
 800 process_target::breakpoint_kind_from_current_state (CORE_ADDR *pcptr)
 801 {
 802   return breakpoint_kind_from_pc (pcptr);
 803 }
 804
 805 const char *
 806 process_target::thread_name (ptid_t thread)
 807 {
 808   return nullptr;
 809 }
 810
 811 bool
 812 process_target::thread_handle (ptid_t ptid, gdb_byte **handle,
 813                                int *handle_len)
 814 {
 815   return false;
 816 }
 817
 818 bool
 819 process_target::supports_software_single_step ()
 820 {
 821   return false;
 822 }