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