aboutsummaryrefslogtreecommitdiff
path: root/gdb/netbsd-nat.c
blob: 9f7a13d9a266eedf2e74f920839a0b56e3ab44c6 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
/* Native-dependent code for NetBSD.

   Copyright (C) 2006-2020 Free Software Foundation, Inc.

   This file is part of GDB.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

#include "defs.h"

#include "netbsd-nat.h"
#include "nat/netbsd-nat.h"
#include "gdbthread.h"
#include "netbsd-tdep.h"
#include "inferior.h"
#include "gdbarch.h"

#include <sys/types.h>
#include <sys/ptrace.h>
#include <sys/sysctl.h>
#include <sys/wait.h>

/* Return the name of a file that can be opened to get the symbols for
   the child process identified by PID.  */

char *
nbsd_nat_target::pid_to_exec_file (int pid)
{
  return const_cast<char *> (netbsd_nat::pid_to_exec_file (pid));
}

/* Return the current directory for the process identified by PID.  */

static std::string
nbsd_pid_to_cwd (int pid)
{
  char buf[PATH_MAX];
  size_t buflen;
  int mib[4] = {CTL_KERN, KERN_PROC_ARGS, pid, KERN_PROC_CWD};
  buflen = sizeof (buf);
  if (sysctl (mib, ARRAY_SIZE (mib), buf, &buflen, NULL, 0))
    return "";
  return buf;
}

/* Return the kinfo_proc2 structure for the process identified by PID.  */

static bool
nbsd_pid_to_kinfo_proc2 (pid_t pid, struct kinfo_proc2 *kp)
{
  gdb_assert (kp != nullptr);

  size_t size = sizeof (*kp);
  int mib[6] = {CTL_KERN, KERN_PROC2, KERN_PROC_PID, pid,
		static_cast<int> (size), 1};
  return !sysctl (mib, ARRAY_SIZE (mib), kp, &size, NULL, 0);
}

/* Return the command line for the process identified by PID.  */

static gdb::unique_xmalloc_ptr<char[]>
nbsd_pid_to_cmdline (int pid)
{
  int mib[4] = {CTL_KERN, KERN_PROC_ARGS, pid, KERN_PROC_ARGV};

  size_t size = 0;
  if (::sysctl (mib, ARRAY_SIZE (mib), NULL, &size, NULL, 0) == -1 || size == 0)
    return nullptr;

  gdb::unique_xmalloc_ptr<char[]> args (XNEWVAR (char, size));

  if (::sysctl (mib, ARRAY_SIZE (mib), args.get (), &size, NULL, 0) == -1
      || size == 0)
    return nullptr;

  /* Arguments are returned as a flattened string with NUL separators.
     Join the arguments with spaces to form a single string.  */
  for (size_t i = 0; i < size - 1; i++)
    if (args[i] == '\0')
      args[i] = ' ';
  args[size - 1] = '\0';

  return args;
}

/* Return true if PTID is still active in the inferior.  */

bool
nbsd_nat_target::thread_alive (ptid_t ptid)
{
  return netbsd_nat::thread_alive (ptid);
}

/* Return the name assigned to a thread by an application.  Returns
   the string in a static buffer.  */

const char *
nbsd_nat_target::thread_name (struct thread_info *thr)
{
  ptid_t ptid = thr->ptid;
  return netbsd_nat::thread_name (ptid);
}

/* Implement the "post_attach" target_ops method.  */

static void
nbsd_add_threads (nbsd_nat_target *target, pid_t pid)
{
  auto fn
    = [&target] (ptid_t ptid)
      {
	if (!in_thread_list (target, ptid))
	  {
	    if (inferior_ptid.lwp () == 0)
	      thread_change_ptid (target, inferior_ptid, ptid);
	    else
	      add_thread (target, ptid);
	  }
      };

  netbsd_nat::for_each_thread (pid, fn);
}

/* Implement the "post_startup_inferior" target_ops method.  */

void
nbsd_nat_target::post_startup_inferior (ptid_t ptid)
{
  netbsd_nat::enable_proc_events (ptid.pid ());
}

/* Implement the "post_attach" target_ops method.  */

void
nbsd_nat_target::post_attach (int pid)
{
  netbsd_nat::enable_proc_events (pid);
  nbsd_add_threads (this, pid);
}

/* Implement the "update_thread_list" target_ops method.  */

void
nbsd_nat_target::update_thread_list ()
{
  delete_exited_threads ();
}

/* Convert PTID to a string.  */

std::string
nbsd_nat_target::pid_to_str (ptid_t ptid)
{
  int lwp = ptid.lwp ();

  if (lwp != 0)
    {
      pid_t pid = ptid.pid ();

      return string_printf ("LWP %d of process %d", lwp, pid);
    }

  return normal_pid_to_str (ptid);
}

/* Retrieve all the memory regions in the specified process.  */

static gdb::unique_xmalloc_ptr<struct kinfo_vmentry[]>
nbsd_kinfo_get_vmmap (pid_t pid, size_t *size)
{
  int mib[5] = {CTL_VM, VM_PROC, VM_PROC_MAP, pid,
		sizeof (struct kinfo_vmentry)};

  size_t length = 0;
  if (sysctl (mib, ARRAY_SIZE (mib), NULL, &length, NULL, 0))
    {
      *size = 0;
      return NULL;
    }

  /* Prereserve more space.  The length argument is volatile and can change
     between the sysctl(3) calls as this function can be called against a
     running process.  */
  length = length * 5 / 3;

  gdb::unique_xmalloc_ptr<struct kinfo_vmentry[]> kiv
    (XNEWVAR (kinfo_vmentry, length));

  if (sysctl (mib, ARRAY_SIZE (mib), kiv.get (), &length, NULL, 0))
    {
      *size = 0;
      return NULL;
    }

  *size = length / sizeof (struct kinfo_vmentry);
  return kiv;
}

/* Iterate over all the memory regions in the current inferior,
   calling FUNC for each memory region.  OBFD is passed as the last
   argument to FUNC.  */

int
nbsd_nat_target::find_memory_regions (find_memory_region_ftype func,
				      void *data)
{
  pid_t pid = inferior_ptid.pid ();

  size_t nitems;
  gdb::unique_xmalloc_ptr<struct kinfo_vmentry[]> vmentl
    = nbsd_kinfo_get_vmmap (pid, &nitems);
  if (vmentl == NULL)
    perror_with_name (_("Couldn't fetch VM map entries."));

  for (size_t i = 0; i < nitems; i++)
    {
      struct kinfo_vmentry *kve = &vmentl[i];

      /* Skip unreadable segments and those where MAP_NOCORE has been set.  */
      if (!(kve->kve_protection & KVME_PROT_READ)
	  || kve->kve_flags & KVME_FLAG_NOCOREDUMP)
	continue;

      /* Skip segments with an invalid type.  */
      switch (kve->kve_type)
	{
	case KVME_TYPE_VNODE:
	case KVME_TYPE_ANON:
	case KVME_TYPE_SUBMAP:
	case KVME_TYPE_OBJECT:
	  break;
	default:
	  continue;
	}

      size_t size = kve->kve_end - kve->kve_start;
      if (info_verbose)
	{
	  fprintf_filtered (gdb_stdout,
			    "Save segment, %ld bytes at %s (%c%c%c)\n",
			    (long) size,
			    paddress (target_gdbarch (), kve->kve_start),
			    kve->kve_protection & KVME_PROT_READ ? 'r' : '-',
			    kve->kve_protection & KVME_PROT_WRITE ? 'w' : '-',
			    kve->kve_protection & KVME_PROT_EXEC ? 'x' : '-');
	}

      /* Invoke the callback function to create the corefile segment.
	 Pass MODIFIED as true, we do not know the real modification state.  */
      func (kve->kve_start, size, kve->kve_protection & KVME_PROT_READ,
	    kve->kve_protection & KVME_PROT_WRITE,
	    kve->kve_protection & KVME_PROT_EXEC, 1, data);
    }
  return 0;
}

/* Implement the "info_proc" target_ops method.  */

bool
nbsd_nat_target::info_proc (const char *args, enum info_proc_what what)
{
  pid_t pid;
  bool do_cmdline = false;
  bool do_cwd = false;
  bool do_exe = false;
  bool do_mappings = false;
  bool do_status = false;

  switch (what)
    {
    case IP_MINIMAL:
      do_cmdline = true;
      do_cwd = true;
      do_exe = true;
      break;
    case IP_STAT:
    case IP_STATUS:
      do_status = true;
      break;
    case IP_MAPPINGS:
      do_mappings = true;
      break;
    case IP_CMDLINE:
      do_cmdline = true;
      break;
    case IP_EXE:
      do_exe = true;
      break;
    case IP_CWD:
      do_cwd = true;
      break;
    case IP_ALL:
      do_cmdline = true;
      do_cwd = true;
      do_exe = true;
      do_mappings = true;
      do_status = true;
      break;
    default:
      error (_("Not supported on this target."));
    }

  gdb_argv built_argv (args);
  if (built_argv.count () == 0)
    {
      pid = inferior_ptid.pid ();
      if (pid == 0)
	error (_("No current process: you must name one."));
    }
  else if (built_argv.count () == 1 && isdigit (built_argv[0][0]))
    pid = strtol (built_argv[0], NULL, 10);
  else
    error (_("Invalid arguments."));

  printf_filtered (_("process %d\n"), pid);

  if (do_cmdline)
    {
      gdb::unique_xmalloc_ptr<char[]> cmdline = nbsd_pid_to_cmdline (pid);
      if (cmdline != nullptr)
	printf_filtered ("cmdline = '%s'\n", cmdline.get ());
      else
	warning (_("unable to fetch command line"));
    }
  if (do_cwd)
    {
      std::string cwd = nbsd_pid_to_cwd (pid);
      if (cwd != "")
	printf_filtered ("cwd = '%s'\n", cwd.c_str ());
      else
	warning (_("unable to fetch current working directory"));
    }
  if (do_exe)
    {
      const char *exe = pid_to_exec_file (pid);
      if (exe != nullptr)
	printf_filtered ("exe = '%s'\n", exe);
      else
	warning (_("unable to fetch executable path name"));
    }
  if (do_mappings)
    {
      size_t nvment;
      gdb::unique_xmalloc_ptr<struct kinfo_vmentry[]> vmentl
	= nbsd_kinfo_get_vmmap (pid, &nvment);

      if (vmentl != nullptr)
	{
	  int addr_bit = TARGET_CHAR_BIT * sizeof (void *);
	  nbsd_info_proc_mappings_header (addr_bit);

	  struct kinfo_vmentry *kve = vmentl.get ();
	  for (int i = 0; i < nvment; i++, kve++)
	    nbsd_info_proc_mappings_entry (addr_bit, kve->kve_start,
					   kve->kve_end, kve->kve_offset,
					   kve->kve_flags, kve->kve_protection,
					   kve->kve_path);
	}
      else
	warning (_("unable to fetch virtual memory map"));
    }
  if (do_status)
    {
      struct kinfo_proc2 kp;
      if (!nbsd_pid_to_kinfo_proc2 (pid, &kp))
	warning (_("Failed to fetch process information"));
      else
	{
	  auto process_status
	    = [] (int8_t stat)
	      {
		switch (stat)
		  {
		  case SIDL:
		    return "IDL";
		  case SACTIVE:
		    return "ACTIVE";
		  case SDYING:
		    return "DYING";
		  case SSTOP:
		    return "STOP";
		  case SZOMB:
		    return "ZOMB";
		  case SDEAD:
		    return "DEAD";
		  default:
		    return "? (unknown)";
		  }
	      };

	  printf_filtered ("Name: %s\n", kp.p_comm);
	  printf_filtered ("State: %s\n", process_status(kp.p_realstat));
	  printf_filtered ("Parent process: %" PRId32 "\n", kp.p_ppid);
	  printf_filtered ("Process group: %" PRId32 "\n", kp.p__pgid);
	  printf_filtered ("Session id: %" PRId32 "\n", kp.p_sid);
	  printf_filtered ("TTY: %" PRId32 "\n", kp.p_tdev);
	  printf_filtered ("TTY owner process group: %" PRId32 "\n", kp.p_tpgid);
	  printf_filtered ("User IDs (real, effective, saved): "
			   "%" PRIu32 " %" PRIu32 " %" PRIu32 "\n",
			   kp.p_ruid, kp.p_uid, kp.p_svuid);
	  printf_filtered ("Group IDs (real, effective, saved): "
			   "%" PRIu32 " %" PRIu32 " %" PRIu32 "\n",
			   kp.p_rgid, kp.p_gid, kp.p_svgid);

	  printf_filtered ("Groups:");
	  for (int i = 0; i < kp.p_ngroups; i++)
	    printf_filtered (" %" PRIu32, kp.p_groups[i]);
	  printf_filtered ("\n");
	  printf_filtered ("Minor faults (no memory page): %" PRIu64 "\n",
			   kp.p_uru_minflt);
	  printf_filtered ("Major faults (memory page faults): %" PRIu64 "\n",
			   kp.p_uru_majflt);
	  printf_filtered ("utime: %" PRIu32 ".%06" PRIu32 "\n",
			   kp.p_uutime_sec, kp.p_uutime_usec);
	  printf_filtered ("stime: %" PRIu32 ".%06" PRIu32 "\n",
			   kp.p_ustime_sec, kp.p_ustime_usec);
	  printf_filtered ("utime+stime, children: %" PRIu32 ".%06" PRIu32 "\n",
			   kp.p_uctime_sec, kp.p_uctime_usec);
	  printf_filtered ("'nice' value: %" PRIu8 "\n", kp.p_nice);
	  printf_filtered ("Start time: %" PRIu32 ".%06" PRIu32 "\n",
			   kp.p_ustart_sec, kp.p_ustart_usec);
	  int pgtok = getpagesize () / 1024;
	  printf_filtered ("Data size: %" PRIuMAX " kB\n",
			   (uintmax_t) kp.p_vm_dsize * pgtok);
	  printf_filtered ("Stack size: %" PRIuMAX " kB\n",
			   (uintmax_t) kp.p_vm_ssize * pgtok);
	  printf_filtered ("Text size: %" PRIuMAX " kB\n",
			   (uintmax_t) kp.p_vm_tsize * pgtok);
	  printf_filtered ("Resident set size: %" PRIuMAX " kB\n",
			   (uintmax_t) kp.p_vm_rssize * pgtok);
	  printf_filtered ("Maximum RSS: %" PRIu64 " kB\n", kp.p_uru_maxrss);
	  printf_filtered ("Pending Signals:");
	  for (size_t i = 0; i < ARRAY_SIZE (kp.p_siglist.__bits); i++)
	    printf_filtered (" %08" PRIx32, kp.p_siglist.__bits[i]);
	  printf_filtered ("\n");
	  printf_filtered ("Ignored Signals:");
	  for (size_t i = 0; i < ARRAY_SIZE (kp.p_sigignore.__bits); i++)
	    printf_filtered (" %08" PRIx32, kp.p_sigignore.__bits[i]);
	  printf_filtered ("\n");
	  printf_filtered ("Caught Signals:");
	  for (size_t i = 0; i < ARRAY_SIZE (kp.p_sigcatch.__bits); i++)
	    printf_filtered (" %08" PRIx32, kp.p_sigcatch.__bits[i]);
	  printf_filtered ("\n");
	}
    }

  return true;
}

/* Resume execution of a specified PTID, that points to a process or a thread
   within a process.  If one thread is specified, all other threads are
   suspended.  If STEP is nonzero, single-step it.  If SIGNAL is nonzero,
   give it that signal.  */

static void
nbsd_resume(nbsd_nat_target *target, ptid_t ptid, int step,
	    enum gdb_signal signal)
{
  int request;

  gdb_assert (minus_one_ptid != ptid);

  if (ptid.lwp_p ())
    {
      /* If ptid is a specific LWP, suspend all other LWPs in the process.  */
      inferior *inf = find_inferior_ptid (target, ptid);

      for (thread_info *tp : inf->non_exited_threads ())
	{
	  if (tp->ptid.lwp () == ptid.lwp ())
	    request = PT_RESUME;
	  else
	    request = PT_SUSPEND;

	  if (ptrace (request, tp->ptid.pid (), NULL, tp->ptid.lwp ()) == -1)
	    perror_with_name (("ptrace"));
	}
    }
  else
    {
      /* If ptid is a wildcard, resume all matching threads (they won't run
	 until the process is continued however).  */
      for (thread_info *tp : all_non_exited_threads (target, ptid))
	if (ptrace (PT_RESUME, tp->ptid.pid (), NULL, tp->ptid.lwp ()) == -1)
	  perror_with_name (("ptrace"));
    }

  if (step)
    {
      for (thread_info *tp : all_non_exited_threads (target, ptid))
	if (ptrace (PT_SETSTEP, tp->ptid.pid (), NULL, tp->ptid.lwp ()) == -1)
	  perror_with_name (("ptrace"));
    }
  else
    {
      for (thread_info *tp : all_non_exited_threads (target, ptid))
	if (ptrace (PT_CLEARSTEP, tp->ptid.pid (), NULL, tp->ptid.lwp ()) == -1)
	  perror_with_name (("ptrace"));
    }

  if (catch_syscall_enabled () > 0)
    request = PT_SYSCALL;
  else
    request = PT_CONTINUE;

  /* An address of (void *)1 tells ptrace to continue from
     where it was.  If GDB wanted it to start some other way, we have
     already written a new program counter value to the child.  */
  if (ptrace (request, ptid.pid (), (void *)1, gdb_signal_to_host (signal)) == -1)
    perror_with_name (("ptrace"));
}

/* Resume execution of thread PTID, or all threads of all inferiors
   if PTID is -1.  If STEP is nonzero, single-step it.  If SIGNAL is nonzero,
   give it that signal.  */

void
nbsd_nat_target::resume (ptid_t ptid, int step, enum gdb_signal signal)
{
  if (minus_one_ptid != ptid)
    nbsd_resume (this, ptid, step, signal);
  else
    {
      for (inferior *inf : all_non_exited_inferiors (this))
	nbsd_resume (this, ptid_t (inf->pid, 0, 0), step, signal);
    }
}

/* Implement a safe wrapper around waitpid().  */

static pid_t
nbsd_wait (ptid_t ptid, struct target_waitstatus *ourstatus,
	   target_wait_flags options)
{
  pid_t pid;
  int status;

  set_sigint_trap ();

  do
    {
      /* The common code passes WNOHANG that leads to crashes, overwrite it.  */
      pid = waitpid (ptid.pid (), &status, 0);
    }
  while (pid == -1 && errno == EINTR);

  clear_sigint_trap ();

  if (pid == -1)
    perror_with_name (_("Child process unexpectedly missing"));

  store_waitstatus (ourstatus, status);
  return pid;
}

/* Wait for the child specified by PTID to do something.  Return the
   process ID of the child, or MINUS_ONE_PTID in case of error; store
   the status in *OURSTATUS.  */

ptid_t
nbsd_nat_target::wait (ptid_t ptid, struct target_waitstatus *ourstatus,
		       target_wait_flags target_options)
{
  pid_t pid = nbsd_wait (ptid, ourstatus, target_options);
  ptid_t wptid = ptid_t (pid);

  /* If the child stopped, keep investigating its status.  */
  if (ourstatus->kind != TARGET_WAITKIND_STOPPED)
    return wptid;

  /* Extract the event and thread that received a signal.  */
  ptrace_siginfo_t psi;
  if (ptrace (PT_GET_SIGINFO, pid, &psi, sizeof (psi)) == -1)
    perror_with_name (("ptrace"));

  /* Pick child's siginfo_t.  */
  siginfo_t *si = &psi.psi_siginfo;

  int lwp = psi.psi_lwpid;

  int signo = si->si_signo;
  const int code = si->si_code;

  /* Construct PTID with a specified thread that received the event.
     If a signal was targeted to the whole process, lwp is 0.  */
  wptid = ptid_t (pid, lwp, 0);

  /* Bail out on non-debugger oriented signals..  */
  if (signo != SIGTRAP)
    return wptid;

  /* Stop examining non-debugger oriented SIGTRAP codes.  */
  if (code <= SI_USER || code == SI_NOINFO)
    return wptid;

  /* Process state for threading events */
  ptrace_state_t pst = {};
  if (code == TRAP_LWP)
    {
      if (ptrace (PT_GET_PROCESS_STATE, pid, &pst, sizeof (pst)) == -1)
	perror_with_name (("ptrace"));
    }

  if (code == TRAP_LWP && pst.pe_report_event == PTRACE_LWP_EXIT)
    {
      /* If GDB attaches to a multi-threaded process, exiting
	 threads might be skipped during post_attach that
	 have not yet reported their PTRACE_LWP_EXIT event.
	 Ignore exited events for an unknown LWP.  */
      thread_info *thr = find_thread_ptid (this, wptid);
      if (thr == nullptr)
	  ourstatus->kind = TARGET_WAITKIND_SPURIOUS;
      else
	{
	  ourstatus->kind = TARGET_WAITKIND_THREAD_EXITED;
	  /* NetBSD does not store an LWP exit status.  */
	  ourstatus->value.integer = 0;

	  if (print_thread_events)
	    printf_unfiltered (_("[%s exited]\n"),
			       target_pid_to_str (wptid).c_str ());
	  delete_thread (thr);
	}

      /* The GDB core expects that the rest of the threads are running.  */
      if (ptrace (PT_CONTINUE, pid, (void *) 1, 0) == -1)
	perror_with_name (("ptrace"));

      return wptid;
    }

  if (in_thread_list (this, ptid_t (pid)))
      thread_change_ptid (this, ptid_t (pid), wptid);

  if (code == TRAP_LWP && pst.pe_report_event == PTRACE_LWP_CREATE)
    {
      /* If GDB attaches to a multi-threaded process, newborn
	 threads might be added by nbsd_add_threads that have
	 not yet reported their PTRACE_LWP_CREATE event.  Ignore
	 born events for an already-known LWP.  */
      if (in_thread_list (this, wptid))
	  ourstatus->kind = TARGET_WAITKIND_SPURIOUS;
      else
	{
	  add_thread (this, wptid);
	  ourstatus->kind = TARGET_WAITKIND_THREAD_CREATED;
	}
      return wptid;
    }

  if (code == TRAP_EXEC)
    {
      ourstatus->kind = TARGET_WAITKIND_EXECD;
      ourstatus->value.execd_pathname = xstrdup (pid_to_exec_file (pid));
      return wptid;
    }

  if (code == TRAP_TRACE)
    {
      /* Unhandled at this level.  */
      return wptid;
    }

  if (code == TRAP_SCE || code == TRAP_SCX)
    {
      int sysnum = si->si_sysnum;

      if (!catch_syscall_enabled () || !catching_syscall_number (sysnum))
	{
	  /* If the core isn't interested in this event, ignore it.  */
	  ourstatus->kind = TARGET_WAITKIND_SPURIOUS;
	  return wptid;
	}

      ourstatus->kind =
	(code == TRAP_SCE) ? TARGET_WAITKIND_SYSCALL_ENTRY :
	TARGET_WAITKIND_SYSCALL_RETURN;
      ourstatus->value.syscall_number = sysnum;
      return wptid;
    }

  if (code == TRAP_BRKPT)
    {
      /* Unhandled at this level.  */
      return wptid;
    }

  /* Unclassified SIGTRAP event.  */
  ourstatus->kind = TARGET_WAITKIND_SPURIOUS;
  return wptid;
}

/* Implement the "insert_exec_catchpoint" target_ops method.  */

int
nbsd_nat_target::insert_exec_catchpoint (int pid)
{
  /* Nothing to do.  */
  return 0;
}

/* Implement the "remove_exec_catchpoint" target_ops method.  */

int
nbsd_nat_target::remove_exec_catchpoint (int pid)
{
  /* Nothing to do.  */
  return 0;
}

/* Implement the "set_syscall_catchpoint" target_ops method.  */

int
nbsd_nat_target::set_syscall_catchpoint (int pid, bool needed,
					 int any_count,
					 gdb::array_view<const int> syscall_counts)
{
  /* Ignore the arguments.  inf-ptrace.c will use PT_SYSCALL which
     will catch all system call entries and exits.  The system calls
     are filtered by GDB rather than the kernel.  */
  return 0;
}

/* Implement the "supports_multi_process" target_ops method. */

bool
nbsd_nat_target::supports_multi_process ()
{
  return true;
}

/* Implement the "xfer_partial" target_ops method.  */

enum target_xfer_status
nbsd_nat_target::xfer_partial (enum target_object object,
			       const char *annex, gdb_byte *readbuf,
			       const gdb_byte *writebuf,
			       ULONGEST offset, ULONGEST len,
			       ULONGEST *xfered_len)
{
  pid_t pid = inferior_ptid.pid ();

  switch (object)
    {
    case TARGET_OBJECT_SIGNAL_INFO:
      {
	len = netbsd_nat::qxfer_siginfo(pid, annex, readbuf, writebuf, offset,
					len);

	if (len == -1)
	  return TARGET_XFER_E_IO;

	*xfered_len = len;
	return TARGET_XFER_OK;
      }
    case TARGET_OBJECT_MEMORY:
      {
	size_t xfered;
	int res;
	if (writebuf != nullptr)
	  res = netbsd_nat::write_memory (pid, writebuf, offset, len, &xfered);
	else
	  res = netbsd_nat::read_memory (pid, readbuf, offset, len, &xfered);
	if (res != 0)
	  {
	    if (res == EACCES)
	      fprintf_unfiltered (gdb_stderr, "Cannot %s process at %s (%s). "
				  "Is PaX MPROTECT active? See security(7), "
				  "sysctl(7), paxctl(8)\n",
				  (writebuf ? "write to" : "read from"),
				  pulongest (offset), safe_strerror (errno));
	    return TARGET_XFER_E_IO;
	  }
	if (xfered == 0)
	  return TARGET_XFER_EOF;
	*xfered_len = (ULONGEST) xfered;
	return TARGET_XFER_OK;
      }
    default:
      return inf_ptrace_target::xfer_partial (object, annex,
					      readbuf, writebuf, offset,
					      len, xfered_len);
    }
}

/* Implement the "supports_dumpcore" target_ops method.  */

bool
nbsd_nat_target::supports_dumpcore ()
{
  return true;
}

/* Implement the "dumpcore" target_ops method.  */

void
nbsd_nat_target::dumpcore (const char *filename)
{
  pid_t pid = inferior_ptid.pid ();

  if (ptrace (PT_DUMPCORE, pid, const_cast<char *>(filename),
	      strlen (filename)) == -1)
    perror_with_name (("ptrace"));
}