gdb/gdbserver/target.c

   1 /* Target operations for the remote server for GDB.
   2    Copyright (C) 2002-2019 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
  24 struct target_ops *the_target;
  25
  26 int
  27 set_desired_thread ()
  28 {
  29   client_state &cs = get_client_state ();
  30   thread_info *found = find_thread_ptid (cs.general_thread);
  31
  32   current_thread = found;
  33   return (current_thread != NULL);
  34 }
  35
  36 /* The thread that was current before prepare_to_access_memory was
  37    called.  done_accessing_memory uses this to restore the previous
  38    selected thread.  */
  39 static ptid_t prev_general_thread;
  40
  41 /* See target.h.  */
  42
  43 int
  44 prepare_to_access_memory (void)
  45 {
  46   client_state &cs = get_client_state ();
  47
  48   /* The first thread found.  */
  49   struct thread_info *first = NULL;
  50   /* The first stopped thread found.  */
  51   struct thread_info *stopped = NULL;
  52   /* The current general thread, if found.  */
  53   struct thread_info *current = NULL;
  54
  55   /* Save the general thread value, since prepare_to_access_memory could change
  56      it.  */
  57   prev_general_thread = cs.general_thread;
  58
  59   if (the_target->prepare_to_access_memory != NULL)
  60     {
  61       int res;
  62
  63       res = the_target->prepare_to_access_memory ();
  64       if (res != 0)
  65         return res;
  66     }
  67
  68   for_each_thread (prev_general_thread.pid (), [&] (thread_info *thread)
  69     {
  70       if (mythread_alive (thread->id))
  71         {
  72           if (stopped == NULL && the_target->thread_stopped != NULL
  73               && thread_stopped (thread))
  74             stopped = thread;
  75
  76           if (first == NULL)
  77             first = thread;
  78
  79           if (current == NULL && prev_general_thread == thread->id)
  80             current = thread;
  81         }
  82     });
  83
  84   /* The thread we end up choosing.  */
  85   struct thread_info *thread;
  86
  87   /* Prefer a stopped thread.  If none is found, try the current
  88      thread.  Otherwise, take the first thread in the process.  If
  89      none is found, undo the effects of
  90      target->prepare_to_access_memory() and return error.  */
  91   if (stopped != NULL)
  92     thread = stopped;
  93   else if (current != NULL)
  94     thread = current;
  95   else if (first != NULL)
  96     thread = first;
  97   else
  98     {
  99       done_accessing_memory ();
 100       return 1;
 101     }
 102
 103   current_thread = thread;
 104   cs.general_thread = ptid_of (thread);
 105
 106   return 0;
 107 }
 108
 109 /* See target.h.  */
 110
 111 void
 112 done_accessing_memory (void)
 113 {
 114   client_state &cs = get_client_state ();
 115
 116   if (the_target->done_accessing_memory != NULL)
 117     the_target->done_accessing_memory ();
 118
 119   /* Restore the previous selected thread.  */
 120   cs.general_thread = prev_general_thread;
 121   switch_to_thread (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 int
 150 write_inferior_memory (CORE_ADDR memaddr, const unsigned char *myaddr,
 151                        int len)
 152 {
 153   /* Make a copy of the data because check_mem_write may need to
 154      update it.  */
 155   std::vector<unsigned char> buffer (myaddr, myaddr + len);
 156   check_mem_write (memaddr, buffer.data (), myaddr, len);
 157   return (*the_target->write_memory) (memaddr, buffer.data (), len);
 158 }
 159
 160 /* See target/target.h.  */
 161
 162 int
 163 target_write_memory (CORE_ADDR memaddr, const gdb_byte *myaddr, ssize_t len)
 164 {
 165   return write_inferior_memory (memaddr, myaddr, len);
 166 }
 167
 168 ptid_t
 169 mywait (ptid_t ptid, struct target_waitstatus *ourstatus, int options,
 170         int connected_wait)
 171 {
 172   ptid_t ret;
 173
 174   if (connected_wait)
 175     server_waiting = 1;
 176
 177   ret = target_wait (ptid, ourstatus, options);
 178
 179   /* We don't expose _LOADED events to gdbserver core.  See the
 180      `dlls_changed' global.  */
 181   if (ourstatus->kind == TARGET_WAITKIND_LOADED)
 182     ourstatus->kind = TARGET_WAITKIND_STOPPED;
 183
 184   /* If GDB is connected through TCP/serial, then GDBserver will most
 185      probably be running on its own terminal/console, so it's nice to
 186      print there why is GDBserver exiting.  If however, GDB is
 187      connected through stdio, then there's no need to spam the GDB
 188      console with this -- the user will already see the exit through
 189      regular GDB output, in that same terminal.  */
 190   if (!remote_connection_is_stdio ())
 191     {
 192       if (ourstatus->kind == TARGET_WAITKIND_EXITED)
 193         fprintf (stderr,
 194                  "\nChild exited with status %d\n", ourstatus->value.integer);
 195       else if (ourstatus->kind == TARGET_WAITKIND_SIGNALLED)
 196         fprintf (stderr, "\nChild terminated with signal = 0x%x (%s)\n",
 197                  gdb_signal_to_host (ourstatus->value.sig),
 198                  gdb_signal_to_name (ourstatus->value.sig));
 199     }
 200
 201   if (connected_wait)
 202     server_waiting = 0;
 203
 204   return ret;
 205 }
 206
 207 /* See target/target.h.  */
 208
 209 void
 210 target_stop_and_wait (ptid_t ptid)
 211 {
 212   struct target_waitstatus status;
 213   int was_non_stop = non_stop;
 214   struct thread_resume resume_info;
 215
 216   resume_info.thread = ptid;
 217   resume_info.kind = resume_stop;
 218   resume_info.sig = GDB_SIGNAL_0;
 219   (*the_target->resume) (&resume_info, 1);
 220
 221   non_stop = 1;
 222   mywait (ptid, &status, 0, 0);
 223   non_stop = was_non_stop;
 224 }
 225
 226 /* See target/target.h.  */
 227
 228 ptid_t
 229 target_wait (ptid_t ptid, struct target_waitstatus *status, int options)
 230 {
 231   return (*the_target->wait) (ptid, status, options);
 232 }
 233
 234 /* See target/target.h.  */
 235
 236 void
 237 target_mourn_inferior (ptid_t ptid)
 238 {
 239   (*the_target->mourn) (find_process_pid (ptid.pid ()));
 240 }
 241
 242 /* See target/target.h.  */
 243
 244 void
 245 target_continue_no_signal (ptid_t ptid)
 246 {
 247   struct thread_resume resume_info;
 248
 249   resume_info.thread = ptid;
 250   resume_info.kind = resume_continue;
 251   resume_info.sig = GDB_SIGNAL_0;
 252   (*the_target->resume) (&resume_info, 1);
 253 }
 254
 255 /* See target/target.h.  */
 256
 257 void
 258 target_continue (ptid_t ptid, enum gdb_signal signal)
 259 {
 260   struct thread_resume resume_info;
 261
 262   resume_info.thread = ptid;
 263   resume_info.kind = resume_continue;
 264   resume_info.sig = gdb_signal_to_host (signal);
 265   (*the_target->resume) (&resume_info, 1);
 266 }
 267
 268 /* See target/target.h.  */
 269
 270 int
 271 target_supports_multi_process (void)
 272 {
 273   return (the_target->supports_multi_process != NULL ?
 274           (*the_target->supports_multi_process) () : 0);
 275 }
 276
 277 int
 278 start_non_stop (int nonstop)
 279 {
 280   if (the_target->start_non_stop == NULL)
 281     {
 282       if (nonstop)
 283         return -1;
 284       else
 285         return 0;
 286     }
 287
 288   return (*the_target->start_non_stop) (nonstop);
 289 }
 290
 291 void
 292 set_target_ops (struct target_ops *target)
 293 {
 294   the_target = XNEW (struct target_ops);
 295   memcpy (the_target, target, sizeof (*the_target));
 296 }
 297
 298 /* Convert pid to printable format.  */
 299
 300 const char *
 301 target_pid_to_str (ptid_t ptid)
 302 {
 303   static char buf[80];
 304
 305   if (ptid == minus_one_ptid)
 306     xsnprintf (buf, sizeof (buf), "<all threads>");
 307   else if (ptid == null_ptid)
 308     xsnprintf (buf, sizeof (buf), "<null thread>");
 309   else if (ptid.tid () != 0)
 310     xsnprintf (buf, sizeof (buf), "Thread %d.0x%lx",
 311                ptid.pid (), ptid.tid ());
 312   else if (ptid.lwp () != 0)
 313     xsnprintf (buf, sizeof (buf), "LWP %d.%ld",
 314                ptid.pid (), ptid.lwp ());
 315   else
 316     xsnprintf (buf, sizeof (buf), "Process %d",
 317                ptid.pid ());
 318
 319   return buf;
 320 }
 321
 322 int
 323 kill_inferior (process_info *proc)
 324 {
 325   gdb_agent_about_to_close (proc->pid);
 326
 327   return (*the_target->kill) (proc);
 328 }
 329
 330 /* Target can do hardware single step.  */
 331
 332 int
 333 target_can_do_hardware_single_step (void)
 334 {
 335   return 1;
 336 }
 337
 338 /* Default implementation for breakpoint_kind_for_pc.
 339
 340    The default behavior for targets that don't implement breakpoint_kind_for_pc
 341    is to use the size of a breakpoint as the kind.  */
 342
 343 int
 344 default_breakpoint_kind_from_pc (CORE_ADDR *pcptr)
 345 {
 346   int size = 0;
 347
 348   gdb_assert (the_target->sw_breakpoint_from_kind != NULL);
 349
 350   (*the_target->sw_breakpoint_from_kind) (0, &size);
 351   return size;
 352 }
 353
 354 /* Define it.  */
 355
 356 target_terminal_state target_terminal::m_terminal_state
 357   = target_terminal_state::is_ours;
 358
 359 /* See target/target.h.  */
 360
 361 void
 362 target_terminal::init ()
 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::inferior ()
 372 {
 373   /* Placeholder needed because of fork_inferior.  Not necessary on
 374      GDBserver.  */
 375 }
 376
 377 /* See target/target.h.  */
 378
 379 void
 380 target_terminal::ours ()
 381 {
 382   /* Placeholder needed because of fork_inferior.  Not necessary on
 383      GDBserver.  */
 384 }
 385
 386 /* See target/target.h.  */
 387
 388 void
 389 target_terminal::ours_for_output (void)
 390 {
 391   /* Placeholder.  */
 392 }
 393
 394 /* See target/target.h.  */
 395
 396 void
 397 target_terminal::info (const char *arg, int from_tty)
 398 {
 399   /* Placeholder.  */
 400 }