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
  26 process_stratum_target *the_target;
  27
  28 int
  29 set_desired_thread ()
  30 {
  31   client_state &cs = get_client_state ();
  32   thread_info *found = find_thread_ptid (cs.general_thread);
  33
  34   current_thread = found;
  35   return (current_thread != NULL);
  36 }
  37
  38 /* The thread that was current before prepare_to_access_memory was
  39    called.  done_accessing_memory uses this to restore the previous
  40    selected thread.  */
  41 static ptid_t prev_general_thread;
  42
  43 /* See target.h.  */
  44
  45 int
  46 prepare_to_access_memory (void)
  47 {
  48   client_state &cs = get_client_state ();
  49
  50   /* The first thread found.  */
  51   struct thread_info *first = NULL;
  52   /* The first stopped thread found.  */
  53   struct thread_info *stopped = NULL;
  54   /* The current general thread, if found.  */
  55   struct thread_info *current = NULL;
  56
  57   /* Save the general thread value, since prepare_to_access_memory could change
  58      it.  */
  59   prev_general_thread = cs.general_thread;
  60
  61   int res = the_target->pt->prepare_to_access_memory ();
  62   if (res != 0)
  63     return res;
  64
  65   for_each_thread (prev_general_thread.pid (), [&] (thread_info *thread)
  66     {
  67       if (mythread_alive (thread->id))
  68         {
  69           if (stopped == NULL && the_target->thread_stopped != NULL
  70               && thread_stopped (thread))
  71             stopped = thread;
  72
  73           if (first == NULL)
  74             first = thread;
  75
  76           if (current == NULL && prev_general_thread == thread->id)
  77             current = thread;
  78         }
  79     });
  80
  81   /* The thread we end up choosing.  */
  82   struct thread_info *thread;
  83
  84   /* Prefer a stopped thread.  If none is found, try the current
  85      thread.  Otherwise, take the first thread in the process.  If
  86      none is found, undo the effects of
  87      target->prepare_to_access_memory() and return error.  */
  88   if (stopped != NULL)
  89     thread = stopped;
  90   else if (current != NULL)
  91     thread = current;
  92   else if (first != NULL)
  93     thread = first;
  94   else
  95     {
  96       done_accessing_memory ();
  97       return 1;
  98     }
  99
 100   current_thread = thread;
 101   cs.general_thread = ptid_of (thread);
 102
 103   return 0;
 104 }
 105
 106 /* See target.h.  */
 107
 108 void
 109 done_accessing_memory (void)
 110 {
 111   client_state &cs = get_client_state ();
 112
 113   the_target->pt->done_accessing_memory ();
 114
 115   /* Restore the previous selected thread.  */
 116   cs.general_thread = prev_general_thread;
 117   switch_to_thread (the_target, cs.general_thread);
 118 }
 119
 120 int
 121 read_inferior_memory (CORE_ADDR memaddr, unsigned char *myaddr, int len)
 122 {
 123   int res;
 124   res = the_target->pt->read_memory (memaddr, myaddr, len);
 125   check_mem_read (memaddr, myaddr, len);
 126   return res;
 127 }
 128
 129 /* See target/target.h.  */
 130
 131 int
 132 target_read_memory (CORE_ADDR memaddr, gdb_byte *myaddr, ssize_t len)
 133 {
 134   return read_inferior_memory (memaddr, myaddr, len);
 135 }
 136
 137 /* See target/target.h.  */
 138
 139 int
 140 target_read_uint32 (CORE_ADDR memaddr, uint32_t *result)
 141 {
 142   return read_inferior_memory (memaddr, (gdb_byte *) result, sizeof (*result));
 143 }
 144
 145 /* See target/target.h.  */
 146
 147 int
 148 target_write_memory (CORE_ADDR memaddr, const unsigned char *myaddr,
 149                      ssize_t len)
 150 {
 151   /* Make a copy of the data because check_mem_write may need to
 152      update it.  */
 153   gdb::byte_vector buffer (myaddr, myaddr + len);
 154   check_mem_write (memaddr, buffer.data (), myaddr, len);
 155   return the_target->pt->write_memory (memaddr, buffer.data (), len);
 156 }
 157
 158 ptid_t
 159 mywait (ptid_t ptid, struct target_waitstatus *ourstatus, int options,
 160         int connected_wait)
 161 {
 162   ptid_t ret;
 163
 164   if (connected_wait)
 165     server_waiting = 1;
 166
 167   ret = target_wait (ptid, ourstatus, options);
 168
 169   /* We don't expose _LOADED events to gdbserver core.  See the
 170      `dlls_changed' global.  */
 171   if (ourstatus->kind == TARGET_WAITKIND_LOADED)
 172     ourstatus->kind = TARGET_WAITKIND_STOPPED;
 173
 174   /* If GDB is connected through TCP/serial, then GDBserver will most
 175      probably be running on its own terminal/console, so it's nice to
 176      print there why is GDBserver exiting.  If however, GDB is
 177      connected through stdio, then there's no need to spam the GDB
 178      console with this -- the user will already see the exit through
 179      regular GDB output, in that same terminal.  */
 180   if (!remote_connection_is_stdio ())
 181     {
 182       if (ourstatus->kind == TARGET_WAITKIND_EXITED)
 183         fprintf (stderr,
 184                  "\nChild exited with status %d\n", ourstatus->value.integer);
 185       else if (ourstatus->kind == TARGET_WAITKIND_SIGNALLED)
 186         fprintf (stderr, "\nChild terminated with signal = 0x%x (%s)\n",
 187                  gdb_signal_to_host (ourstatus->value.sig),
 188                  gdb_signal_to_name (ourstatus->value.sig));
 189     }
 190
 191   if (connected_wait)
 192     server_waiting = 0;
 193
 194   return ret;
 195 }
 196
 197 /* See target/target.h.  */
 198
 199 void
 200 target_stop_and_wait (ptid_t ptid)
 201 {
 202   struct target_waitstatus status;
 203   bool was_non_stop = non_stop;
 204   struct thread_resume resume_info;
 205
 206   resume_info.thread = ptid;
 207   resume_info.kind = resume_stop;
 208   resume_info.sig = GDB_SIGNAL_0;
 209   the_target->pt->resume (&resume_info, 1);
 210
 211   non_stop = true;
 212   mywait (ptid, &status, 0, 0);
 213   non_stop = was_non_stop;
 214 }
 215
 216 /* See target/target.h.  */
 217
 218 ptid_t
 219 target_wait (ptid_t ptid, struct target_waitstatus *status, int options)
 220 {
 221   return the_target->pt->wait (ptid, status, options);
 222 }
 223
 224 /* See target/target.h.  */
 225
 226 void
 227 target_mourn_inferior (ptid_t ptid)
 228 {
 229   the_target->pt->mourn (find_process_pid (ptid.pid ()));
 230 }
 231
 232 /* See target/target.h.  */
 233
 234 void
 235 target_continue_no_signal (ptid_t ptid)
 236 {
 237   struct thread_resume resume_info;
 238
 239   resume_info.thread = ptid;
 240   resume_info.kind = resume_continue;
 241   resume_info.sig = GDB_SIGNAL_0;
 242   the_target->pt->resume (&resume_info, 1);
 243 }
 244
 245 /* See target/target.h.  */
 246
 247 void
 248 target_continue (ptid_t ptid, enum gdb_signal signal)
 249 {
 250   struct thread_resume resume_info;
 251
 252   resume_info.thread = ptid;
 253   resume_info.kind = resume_continue;
 254   resume_info.sig = gdb_signal_to_host (signal);
 255   the_target->pt->resume (&resume_info, 1);
 256 }
 257
 258 /* See target/target.h.  */
 259
 260 int
 261 target_supports_multi_process (void)
 262 {
 263   return (the_target->supports_multi_process != NULL ?
 264           (*the_target->supports_multi_process) () : 0);
 265 }
 266
 267 int
 268 start_non_stop (int nonstop)
 269 {
 270   if (the_target->start_non_stop == NULL)
 271     {
 272       if (nonstop)
 273         return -1;
 274       else
 275         return 0;
 276     }
 277
 278   return (*the_target->start_non_stop) (nonstop);
 279 }
 280
 281 void
 282 set_target_ops (process_stratum_target *target)
 283 {
 284   the_target = XNEW (process_stratum_target);
 285   memcpy (the_target, target, sizeof (*the_target));
 286 }
 287
 288 /* Convert pid to printable format.  */
 289
 290 const char *
 291 target_pid_to_str (ptid_t ptid)
 292 {
 293   static char buf[80];
 294
 295   if (ptid == minus_one_ptid)
 296     xsnprintf (buf, sizeof (buf), "<all threads>");
 297   else if (ptid == null_ptid)
 298     xsnprintf (buf, sizeof (buf), "<null thread>");
 299   else if (ptid.tid () != 0)
 300     xsnprintf (buf, sizeof (buf), "Thread %d.0x%lx",
 301                ptid.pid (), ptid.tid ());
 302   else if (ptid.lwp () != 0)
 303     xsnprintf (buf, sizeof (buf), "LWP %d.%ld",
 304                ptid.pid (), ptid.lwp ());
 305   else
 306     xsnprintf (buf, sizeof (buf), "Process %d",
 307                ptid.pid ());
 308
 309   return buf;
 310 }
 311
 312 int
 313 kill_inferior (process_info *proc)
 314 {
 315   gdb_agent_about_to_close (proc->pid);
 316
 317   return the_target->pt->kill (proc);
 318 }
 319
 320 /* Default implementation for breakpoint_kind_for_pc.
 321
 322    The default behavior for targets that don't implement breakpoint_kind_for_pc
 323    is to use the size of a breakpoint as the kind.  */
 324
 325 int
 326 default_breakpoint_kind_from_pc (CORE_ADDR *pcptr)
 327 {
 328   int size = 0;
 329
 330   gdb_assert (the_target->sw_breakpoint_from_kind != NULL);
 331
 332   (*the_target->sw_breakpoint_from_kind) (0, &size);
 333   return size;
 334 }
 335
 336 /* Define it.  */
 337
 338 target_terminal_state target_terminal::m_terminal_state
 339   = target_terminal_state::is_ours;
 340
 341 /* See target/target.h.  */
 342
 343 void
 344 target_terminal::init ()
 345 {
 346   /* Placeholder needed because of fork_inferior.  Not necessary on
 347      GDBserver.  */
 348 }
 349
 350 /* See target/target.h.  */
 351
 352 void
 353 target_terminal::inferior ()
 354 {
 355   /* Placeholder needed because of fork_inferior.  Not necessary on
 356      GDBserver.  */
 357 }
 358
 359 /* See target/target.h.  */
 360
 361 void
 362 target_terminal::ours ()
 363 {
 364   /* Placeholder needed because of fork_inferior.  Not necessary on
 365      GDBserver.  */
 366 }
 367
 368 /* See target/target.h.  */
 369
 370 void
 371 target_terminal::ours_for_output (void)
 372 {
 373   /* Placeholder.  */
 374 }
 375
 376 /* See target/target.h.  */
 377
 378 void
 379 target_terminal::info (const char *arg, int from_tty)
 380 {
 381   /* Placeholder.  */
 382 }
 383
 384 /* Default implementations of target ops.
 385    See target.h for definitions.  */
 386
 387 void
 388 process_target::post_create_inferior ()
 389 {
 390   /* Nop.  */
 391 }
 392
 393 int
 394 process_target::prepare_to_access_memory ()
 395 {
 396   return 0;
 397 }
 398
 399 void
 400 process_target::done_accessing_memory ()
 401 {
 402   /* Nop.  */
 403 }
 404
 405 void
 406 process_target::look_up_symbols ()
 407 {
 408   /* Nop.  */
 409 }
 410
 411 bool
 412 process_target::supports_read_auxv ()
 413 {
 414   return false;
 415 }
 416
 417 int
 418 process_target::read_auxv (CORE_ADDR offset, unsigned char *myaddr,
 419                            unsigned int len)
 420 {
 421   gdb_assert_not_reached ("target op read_auxv not supported");
 422 }
 423
 424 bool
 425 process_target::supports_z_point_type (char z_type)
 426 {
 427   return false;
 428 }
 429
 430 int
 431 process_target::insert_point (enum raw_bkpt_type type, CORE_ADDR addr,
 432                               int size, raw_breakpoint *bp)
 433 {
 434   return 1;
 435 }
 436
 437 int
 438 process_target::remove_point (enum raw_bkpt_type type, CORE_ADDR addr,
 439                               int size, raw_breakpoint *bp)
 440 {
 441   return 1;
 442 }
 443
 444 bool
 445 process_target::stopped_by_sw_breakpoint ()
 446 {
 447   return false;
 448 }
 449
 450 bool
 451 process_target::supports_stopped_by_sw_breakpoint ()
 452 {
 453   return false;
 454 }
 455
 456 bool
 457 process_target::stopped_by_hw_breakpoint ()
 458 {
 459   return false;
 460 }
 461
 462 bool
 463 process_target::supports_stopped_by_hw_breakpoint ()
 464 {
 465   return false;
 466 }
 467
 468 bool
 469 process_target::supports_hardware_single_step ()
 470 {
 471   return false;
 472 }
 473
 474 bool
 475 process_target::stopped_by_watchpoint ()
 476 {
 477   return false;
 478 }
 479
 480 CORE_ADDR
 481 process_target::stopped_data_address ()
 482 {
 483   return 0;
 484 }
 485
 486 bool
 487 process_target::supports_read_offsets ()
 488 {
 489   return false;
 490 }
 491
 492 int
 493 process_target::read_offsets (CORE_ADDR *text, CORE_ADDR *data)
 494 {
 495   gdb_assert_not_reached ("target op read_offsets not supported");
 496 }
 497
 498 bool
 499 process_target::supports_get_tls_address ()
 500 {
 501   return false;
 502 }
 503
 504 int
 505 process_target::get_tls_address (thread_info *thread, CORE_ADDR offset,
 506                                  CORE_ADDR load_module, CORE_ADDR *address)
 507 {
 508   gdb_assert_not_reached ("target op get_tls_address not supported");
 509 }
 510
 511 void
 512 process_target::hostio_last_error (char *buf)
 513 {
 514   hostio_last_error_from_errno (buf);
 515 }