aboutsummaryrefslogtreecommitdiff
path: root/gdb/sol-thread.c
blob: bb33a20ea5227f552cd4e1cd835e71cfc1a92482 (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
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
/* Solaris threads debugging interface.

   Copyright (C) 1996-2020 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/>.  */

/* This module implements a sort of half target that sits between the
   machine-independent parts of GDB and the /proc interface (procfs.c)
   to provide access to the Solaris user-mode thread implementation.

   Solaris threads are true user-mode threads, which are invoked via
   the thr_* and pthread_* (native and POSIX respectively) interfaces.
   These are mostly implemented in user-space, with all thread context
   kept in various structures that live in the user's heap.  These
   should not be confused with lightweight processes (LWPs), which are
   implemented by the kernel, and scheduled without explicit
   intervention by the process.

   Just to confuse things a little, Solaris threads (both native and
   POSIX) are actually implemented using LWPs.  In general, there are
   going to be more threads than LWPs.  There is no fixed
   correspondence between a thread and an LWP.  When a thread wants to
   run, it gets scheduled onto the first available LWP and can
   therefore migrate from one LWP to another as time goes on.  A
   sleeping thread may not be associated with an LWP at all!

   To make it possible to mess with threads, Sun provides a library
   called libthread_db.so.1 (not to be confused with
   libthread_db.so.0, which doesn't have a published interface).  This
   interface has an upper part, which it provides, and a lower part
   which we provide.  The upper part consists of the td_* routines,
   which allow us to find all the threads, query their state, etc...
   The lower part consists of all of the ps_*, which are used by the
   td_* routines to read/write memory, manipulate LWPs, lookup
   symbols, etc...  The ps_* routines actually do most of their work
   by calling functions in procfs.c.  */

#include "defs.h"
#include <thread.h>
#include <proc_service.h>
#include <thread_db.h>
#include "gdbthread.h"
#include "target.h"
#include "inferior.h"
#include <fcntl.h>
#include <sys/stat.h>
#include <dlfcn.h>
#include "gdbcmd.h"
#include "gdbcore.h"
#include "regcache.h"
#include "solib.h"
#include "symfile.h"
#include "observable.h"
#include "procfs.h"
#include "symtab.h"
#include "minsyms.h"
#include "objfiles.h"

static const target_info thread_db_target_info = {
  "solaris-threads",
  N_("Solaris threads and pthread."),
  N_("Solaris threads and pthread support.")
};

class sol_thread_target final : public target_ops
{
public:
  const target_info &info () const override
  { return thread_db_target_info; }

  strata stratum () const override { return thread_stratum; }

  void detach (inferior *, int) override;
  ptid_t wait (ptid_t, struct target_waitstatus *, target_wait_flags) override;
  void resume (ptid_t, int, enum gdb_signal) override;
  void mourn_inferior () override;
  std::string pid_to_str (ptid_t) override;
  ptid_t get_ada_task_ptid (long lwp, long thread) override;

  void fetch_registers (struct regcache *, int) override;
  void store_registers (struct regcache *, int) override;

  enum target_xfer_status xfer_partial (enum target_object object,
					const char *annex,
					gdb_byte *readbuf,
					const gdb_byte *writebuf,
					ULONGEST offset, ULONGEST len,
					ULONGEST *xfered_len) override;

  bool thread_alive (ptid_t ptid) override;
  void update_thread_list () override;
};

static sol_thread_target sol_thread_ops;

/* Prototypes for supply_gregset etc.  */
#include "gregset.h"

/* This struct is defined by us, but mainly used for the proc_service
   interface.  We don't have much use for it, except as a handy place
   to get a real PID for memory accesses.  */

struct ps_prochandle
{
  ptid_t ptid;
};

struct string_map
{
  int num;
  const char *str;
};

static struct ps_prochandle main_ph;
static td_thragent_t *main_ta;
static int sol_thread_active = 0;

/* Default definitions: These must be defined in tm.h if they are to
   be shared with a process module such as procfs.  */

/* Types of the libthread_db functions.  */

typedef void (td_log_ftype)(const int on_off);
typedef td_err_e (td_ta_new_ftype)(const struct ps_prochandle *ph_p,
				   td_thragent_t **ta_pp);
typedef td_err_e (td_ta_delete_ftype)(td_thragent_t *ta_p);
typedef td_err_e (td_init_ftype)(void);
typedef td_err_e (td_ta_get_ph_ftype)(const td_thragent_t *ta_p,
				      struct ps_prochandle **ph_pp);
typedef td_err_e (td_ta_get_nthreads_ftype)(const td_thragent_t *ta_p,
					    int *nthread_p);
typedef td_err_e (td_ta_tsd_iter_ftype)(const td_thragent_t *ta_p,
					td_key_iter_f *cb, void *cbdata_p);
typedef td_err_e (td_ta_thr_iter_ftype)(const td_thragent_t *ta_p,
					td_thr_iter_f *cb, void *cbdata_p,
					td_thr_state_e state, int ti_pri,
					sigset_t *ti_sigmask_p,
					unsigned ti_user_flags);
typedef td_err_e (td_thr_validate_ftype)(const td_thrhandle_t *th_p);
typedef td_err_e (td_thr_tsd_ftype)(const td_thrhandle_t * th_p,
				    const thread_key_t key, void **data_pp);
typedef td_err_e (td_thr_get_info_ftype)(const td_thrhandle_t *th_p,
					 td_thrinfo_t *ti_p);
typedef td_err_e (td_thr_getfpregs_ftype)(const td_thrhandle_t *th_p,
					  prfpregset_t *fpregset);
typedef td_err_e (td_thr_getxregsize_ftype)(const td_thrhandle_t *th_p,
					    int *xregsize);
typedef td_err_e (td_thr_getxregs_ftype)(const td_thrhandle_t *th_p,
					 const caddr_t xregset);
typedef td_err_e (td_thr_sigsetmask_ftype)(const td_thrhandle_t *th_p,
					   const sigset_t ti_sigmask);
typedef td_err_e (td_thr_setprio_ftype)(const td_thrhandle_t *th_p,
					const int ti_pri);
typedef td_err_e (td_thr_setsigpending_ftype)(const td_thrhandle_t *th_p,
					      const uchar_t ti_pending_flag,
					      const sigset_t ti_pending);
typedef td_err_e (td_thr_setfpregs_ftype)(const td_thrhandle_t *th_p,
					  const prfpregset_t *fpregset);
typedef td_err_e (td_thr_setxregs_ftype)(const td_thrhandle_t *th_p,
					 const caddr_t xregset);
typedef td_err_e (td_ta_map_id2thr_ftype)(const td_thragent_t *ta_p,
					  thread_t tid,
					  td_thrhandle_t *th_p);
typedef td_err_e (td_ta_map_lwp2thr_ftype)(const td_thragent_t *ta_p,
					   lwpid_t lwpid,
					   td_thrhandle_t *th_p);
typedef td_err_e (td_thr_getgregs_ftype)(const td_thrhandle_t *th_p,
					 prgregset_t regset);
typedef td_err_e (td_thr_setgregs_ftype)(const td_thrhandle_t *th_p,
					 const prgregset_t regset);

/* Pointers to routines from libthread_db resolved by dlopen().  */

static td_log_ftype *p_td_log;
static td_ta_new_ftype *p_td_ta_new;
static td_ta_delete_ftype *p_td_ta_delete;
static td_init_ftype *p_td_init;
static td_ta_get_ph_ftype *p_td_ta_get_ph;
static td_ta_get_nthreads_ftype *p_td_ta_get_nthreads;
static td_ta_tsd_iter_ftype *p_td_ta_tsd_iter;
static td_ta_thr_iter_ftype *p_td_ta_thr_iter;
static td_thr_validate_ftype *p_td_thr_validate;
static td_thr_tsd_ftype *p_td_thr_tsd;
static td_thr_get_info_ftype *p_td_thr_get_info;
static td_thr_getfpregs_ftype *p_td_thr_getfpregs;
static td_thr_getxregsize_ftype *p_td_thr_getxregsize;
static td_thr_getxregs_ftype *p_td_thr_getxregs;
static td_thr_sigsetmask_ftype *p_td_thr_sigsetmask;
static td_thr_setprio_ftype *p_td_thr_setprio;
static td_thr_setsigpending_ftype *p_td_thr_setsigpending;
static td_thr_setfpregs_ftype *p_td_thr_setfpregs;
static td_thr_setxregs_ftype *p_td_thr_setxregs;
static td_ta_map_id2thr_ftype *p_td_ta_map_id2thr;
static td_ta_map_lwp2thr_ftype *p_td_ta_map_lwp2thr;
static td_thr_getgregs_ftype *p_td_thr_getgregs;
static td_thr_setgregs_ftype *p_td_thr_setgregs;


/* Return the libthread_db error string associated with ERRCODE.  If
   ERRCODE is unknown, return an appropriate message.  */

static const char *
td_err_string (td_err_e errcode)
{
  static struct string_map td_err_table[] =
  {
    { TD_OK, "generic \"call succeeded\"" },
    { TD_ERR, "generic error." },
    { TD_NOTHR, "no thread can be found to satisfy query" },
    { TD_NOSV, "no synch. variable can be found to satisfy query" },
    { TD_NOLWP, "no lwp can be found to satisfy query" },
    { TD_BADPH, "invalid process handle" },
    { TD_BADTH, "invalid thread handle" },
    { TD_BADSH, "invalid synchronization handle" },
    { TD_BADTA, "invalid thread agent" },
    { TD_BADKEY, "invalid key" },
    { TD_NOMSG, "td_thr_event_getmsg() called when there was no message" },
    { TD_NOFPREGS, "FPU register set not available for given thread" },
    { TD_NOLIBTHREAD, "application not linked with libthread" },
    { TD_NOEVENT, "requested event is not supported" },
    { TD_NOCAPAB, "capability not available" },
    { TD_DBERR, "Debugger service failed" },
    { TD_NOAPLIC, "Operation not applicable to" },
    { TD_NOTSD, "No thread specific data for this thread" },
    { TD_MALLOC, "Malloc failed" },
    { TD_PARTIALREG, "Only part of register set was written/read" },
    { TD_NOXREGS, "X register set not available for given thread" }
  };
  const int td_err_size = sizeof td_err_table / sizeof (struct string_map);
  int i;
  static char buf[50];

  for (i = 0; i < td_err_size; i++)
    if (td_err_table[i].num == errcode)
      return td_err_table[i].str;

  xsnprintf (buf, sizeof (buf), "Unknown libthread_db error code: %d",
	     errcode);

  return buf;
}

/* Return the libthread_db state string associated with STATECODE.
   If STATECODE is unknown, return an appropriate message.  */

static const char *
td_state_string (td_thr_state_e statecode)
{
  static struct string_map td_thr_state_table[] =
  {
    { TD_THR_ANY_STATE, "any state" },
    { TD_THR_UNKNOWN, "unknown" },
    { TD_THR_STOPPED, "stopped" },
    { TD_THR_RUN, "run" },
    { TD_THR_ACTIVE, "active" },
    { TD_THR_ZOMBIE, "zombie" },
    { TD_THR_SLEEP, "sleep" },
    { TD_THR_STOPPED_ASLEEP, "stopped asleep" }
  };
  const int td_thr_state_table_size =
    sizeof td_thr_state_table / sizeof (struct string_map);
  int i;
  static char buf[50];

  for (i = 0; i < td_thr_state_table_size; i++)
    if (td_thr_state_table[i].num == statecode)
      return td_thr_state_table[i].str;

  xsnprintf (buf, sizeof (buf), "Unknown libthread_db state code: %d",
	     statecode);

  return buf;
}


/* Convert a POSIX or Solaris thread ID into a LWP ID.  If THREAD_ID
   doesn't exist, that's an error.  If it's an inactive thread, return
   DEFAULT_LWP.

   NOTE: This function probably shouldn't call error().  */

static ptid_t
thread_to_lwp (ptid_t thread_id, int default_lwp)
{
  td_thrinfo_t ti;
  td_thrhandle_t th;
  td_err_e val;

  if (thread_id.lwp_p ())
    return thread_id;		/* It's already an LWP ID.  */

  /* It's a thread.  Convert to LWP.  */

  val = p_td_ta_map_id2thr (main_ta, thread_id.tid (), &th);
  if (val == TD_NOTHR)
    return ptid_t (-1);	/* Thread must have terminated.  */
  else if (val != TD_OK)
    error (_("thread_to_lwp: td_ta_map_id2thr %s"), td_err_string (val));

  val = p_td_thr_get_info (&th, &ti);
  if (val == TD_NOTHR)
    return ptid_t (-1);	/* Thread must have terminated.  */
  else if (val != TD_OK)
    error (_("thread_to_lwp: td_thr_get_info: %s"), td_err_string (val));

  if (ti.ti_state != TD_THR_ACTIVE)
    {
      if (default_lwp != -1)
	return ptid_t (default_lwp);
      error (_("thread_to_lwp: thread state not active: %s"),
	     td_state_string (ti.ti_state));
    }

  return ptid_t (thread_id.pid (), ti.ti_lid, 0);
}

/* Convert an LWP ID into a POSIX or Solaris thread ID.  If LWP_ID
   doesn't exists, that's an error.

   NOTE: This function probably shouldn't call error().  */

static ptid_t
lwp_to_thread (ptid_t lwp)
{
  td_thrinfo_t ti;
  td_thrhandle_t th;
  td_err_e val;

  if (lwp.tid_p ())
    return lwp;			/* It's already a thread ID.  */

  /* It's an LWP.  Convert it to a thread ID.  */

  if (!target_thread_alive (lwp))
    return ptid_t (-1);	/* Must be a defunct LPW.  */

  val = p_td_ta_map_lwp2thr (main_ta, lwp.lwp (), &th);
  if (val == TD_NOTHR)
    return ptid_t (-1);	/* Thread must have terminated.  */
  else if (val != TD_OK)
    error (_("lwp_to_thread: td_ta_map_lwp2thr: %s."), td_err_string (val));

  val = p_td_thr_validate (&th);
  if (val == TD_NOTHR)
    return lwp;			/* Unknown to libthread; just return LPW,  */
  else if (val != TD_OK)
    error (_("lwp_to_thread: td_thr_validate: %s."), td_err_string (val));

  val = p_td_thr_get_info (&th, &ti);
  if (val == TD_NOTHR)
    return ptid_t (-1);	/* Thread must have terminated.  */
  else if (val != TD_OK)
    error (_("lwp_to_thread: td_thr_get_info: %s."), td_err_string (val));

  return ptid_t (lwp.pid (), 0 , ti.ti_tid);
}


/* Most target vector functions from here on actually just pass
   through to the layer beneath, as they don't need to do anything
   specific for threads.  */

/* Take a program previously attached to and detaches it.  The program
   resumes execution and will no longer stop on signals, etc.  We'd
   better not have left any breakpoints in the program or it'll die
   when it hits one.  For this to work, it may be necessary for the
   process to have been previously attached.  It *might* work if the
   program was started via the normal ptrace (PTRACE_TRACEME).  */

void
sol_thread_target::detach (inferior *inf, int from_tty)
{
  target_ops *beneath = this->beneath ();

  sol_thread_active = 0;
  inferior_ptid = ptid_t (main_ph.ptid.pid ());
  unpush_target (this);
  beneath->detach (inf, from_tty);
}

/* Resume execution of process PTID.  If STEP is nonzero, then just
   single step it.  If SIGNAL is nonzero, restart it with that signal
   activated.  We may have to convert PTID from a thread ID to an LWP
   ID for procfs.  */

void
sol_thread_target::resume (ptid_t ptid, int step, enum gdb_signal signo)
{
  scoped_restore save_inferior_ptid = make_scoped_restore (&inferior_ptid);

  inferior_ptid = thread_to_lwp (inferior_ptid, main_ph.ptid.pid ());
  if (inferior_ptid.pid () == -1)
    inferior_ptid = procfs_first_available ();

  if (ptid.pid () != -1)
    {
      ptid_t save_ptid = ptid;

      ptid = thread_to_lwp (ptid, -2);
      if (ptid.pid () == -2)		/* Inactive thread.  */
	error (_("This version of Solaris can't start inactive threads."));
      if (info_verbose && ptid.pid () == -1)
	warning (_("Specified thread %ld seems to have terminated"),
		 save_ptid.tid ());
    }

  beneath ()->resume (ptid, step, signo);
}

/* Wait for any threads to stop.  We may have to convert PTID from a
   thread ID to an LWP ID, and vice versa on the way out.  */

ptid_t
sol_thread_target::wait (ptid_t ptid, struct target_waitstatus *ourstatus,
			 target_wait_flags options)
{
  if (ptid.pid () != -1)
    {
      ptid_t ptid_for_warning = ptid;

      ptid = thread_to_lwp (ptid, -2);
      if (ptid.pid () == -2)		/* Inactive thread.  */
	error (_("This version of Solaris can't start inactive threads."));
      if (info_verbose && ptid.pid () == -1)
	warning (_("Specified thread %ld seems to have terminated"),
		 ptid_for_warning.tid ());
    }

  ptid_t rtnval = beneath ()->wait (ptid, ourstatus, options);

  if (ourstatus->kind != TARGET_WAITKIND_EXITED)
    {
      /* Map the LWP of interest back to the appropriate thread ID.  */
      ptid_t thr_ptid = lwp_to_thread (rtnval);
      if (thr_ptid.pid () != -1)
	rtnval = thr_ptid;

      /* See if we have a new thread.  */
      if (rtnval.tid_p ())
	{
	  thread_info *thr = find_thread_ptid (current_inferior (), rtnval);
	  if (thr == NULL || thr->state == THREAD_EXITED)
	    {
	      process_stratum_target *proc_target
		= current_inferior ()->process_target ();
	      add_thread (proc_target, rtnval);
	    }
	}
    }

  /* During process initialization, we may get here without the thread
     package being initialized, since that can only happen after we've
     found the shared libs.  */

  return rtnval;
}

void
sol_thread_target::fetch_registers (struct regcache *regcache, int regnum)
{
  thread_t thread;
  td_thrhandle_t thandle;
  td_err_e val;
  prgregset_t gregset;
  prfpregset_t fpregset;
  gdb_gregset_t *gregset_p = &gregset;
  gdb_fpregset_t *fpregset_p = &fpregset;
  ptid_t ptid = regcache->ptid ();

  if (!ptid.tid_p ())
    {
      /* It's an LWP; pass the request on to the layer beneath.  */
      beneath ()->fetch_registers (regcache, regnum);
      return;
    }

  /* Solaris thread: convert PTID into a td_thrhandle_t.  */
  thread = ptid.tid ();
  if (thread == 0)
    error (_("sol_thread_fetch_registers: thread == 0"));

  val = p_td_ta_map_id2thr (main_ta, thread, &thandle);
  if (val != TD_OK)
    error (_("sol_thread_fetch_registers: td_ta_map_id2thr: %s"),
	   td_err_string (val));

  /* Get the general-purpose registers.  */

  val = p_td_thr_getgregs (&thandle, gregset);
  if (val != TD_OK && val != TD_PARTIALREG)
    error (_("sol_thread_fetch_registers: td_thr_getgregs %s"),
	   td_err_string (val));

  /* For SPARC, TD_PARTIALREG means that only %i0...%i7, %l0..%l7, %pc
     and %sp are saved (by a thread context switch).  */

  /* And, now the floating-point registers.  */

  val = p_td_thr_getfpregs (&thandle, &fpregset);
  if (val != TD_OK && val != TD_NOFPREGS)
    error (_("sol_thread_fetch_registers: td_thr_getfpregs %s"),
	   td_err_string (val));

  /* Note that we must call supply_gregset and supply_fpregset *after*
     calling the td routines because the td routines call ps_lget*
     which affect the values stored in the registers array.  */

  supply_gregset (regcache, (const gdb_gregset_t *) gregset_p);
  supply_fpregset (regcache, (const gdb_fpregset_t *) fpregset_p);
}

void
sol_thread_target::store_registers (struct regcache *regcache, int regnum)
{
  thread_t thread;
  td_thrhandle_t thandle;
  td_err_e val;
  prgregset_t gregset;
  prfpregset_t fpregset;
  ptid_t ptid = regcache->ptid ();

  if (!ptid.tid_p ())
    {
      /* It's an LWP; pass the request on to the layer beneath.  */
      beneath ()->store_registers (regcache, regnum);
      return;
    }

  /* Solaris thread: convert PTID into a td_thrhandle_t.  */
  thread = ptid.tid ();

  val = p_td_ta_map_id2thr (main_ta, thread, &thandle);
  if (val != TD_OK)
    error (_("sol_thread_store_registers: td_ta_map_id2thr %s"),
	   td_err_string (val));

  if (regnum != -1)
    {
      val = p_td_thr_getgregs (&thandle, gregset);
      if (val != TD_OK)
	error (_("sol_thread_store_registers: td_thr_getgregs %s"),
	       td_err_string (val));
      val = p_td_thr_getfpregs (&thandle, &fpregset);
      if (val != TD_OK)
	error (_("sol_thread_store_registers: td_thr_getfpregs %s"),
	       td_err_string (val));
    }

  fill_gregset (regcache, (gdb_gregset_t *) &gregset, regnum);
  fill_fpregset (regcache, (gdb_fpregset_t *) &fpregset, regnum);

  val = p_td_thr_setgregs (&thandle, gregset);
  if (val != TD_OK)
    error (_("sol_thread_store_registers: td_thr_setgregs %s"),
	   td_err_string (val));
  val = p_td_thr_setfpregs (&thandle, &fpregset);
  if (val != TD_OK)
    error (_("sol_thread_store_registers: td_thr_setfpregs %s"),
	   td_err_string (val));
}

/* Perform partial transfers on OBJECT.  See target_read_partial and
   target_write_partial for details of each variant.  One, and only
   one, of readbuf or writebuf must be non-NULL.  */

enum target_xfer_status
sol_thread_target::xfer_partial (enum target_object object,
				 const char *annex, gdb_byte *readbuf,
				 const gdb_byte *writebuf,
				 ULONGEST offset, ULONGEST len,
				 ULONGEST *xfered_len)
{
  scoped_restore save_inferior_ptid = make_scoped_restore (&inferior_ptid);

  if (inferior_ptid.tid_p () || !target_thread_alive (inferior_ptid))
    {
      /* It's either a thread or an LWP that isn't alive.  Any live
         LWP will do so use the first available.

	 NOTE: We don't need to call switch_to_thread; we're just
	 reading memory.  */
      inferior_ptid = procfs_first_available ();
    }

  return beneath ()->xfer_partial (object, annex, readbuf,
				   writebuf, offset, len, xfered_len);
}

static void
check_for_thread_db (void)
{
  td_err_e err;
  ptid_t ptid;

  /* Don't attempt to use thread_db for remote targets.  */
  if (!(target_can_run () || core_bfd))
    return;

  /* Do nothing if we couldn't load libthread_db.so.1.  */
  if (p_td_ta_new == NULL)
    return;

  if (sol_thread_active)
    /* Nothing to do.  The thread library was already detected and the
       target vector was already activated.  */
    return;

  /* Now, initialize libthread_db.  This needs to be done after the
     shared libraries are located because it needs information from
     the user's thread library.  */

  err = p_td_init ();
  if (err != TD_OK)
    {
      warning (_("sol_thread_new_objfile: td_init: %s"), td_err_string (err));
      return;
    }

  /* Now attempt to open a connection to the thread library.  */
  err = p_td_ta_new (&main_ph, &main_ta);
  switch (err)
    {
    case TD_NOLIBTHREAD:
      /* No thread library was detected.  */
      break;

    case TD_OK:
      printf_unfiltered (_("[Thread debugging using libthread_db enabled]\n"));

      /* The thread library was detected.  Activate the sol_thread target.  */
      push_target (&sol_thread_ops);
      sol_thread_active = 1;

      main_ph.ptid = inferior_ptid; /* Save for xfer_memory.  */
      ptid = lwp_to_thread (inferior_ptid);
      if (ptid.pid () != -1)
	inferior_ptid = ptid;

      target_update_thread_list ();
      break;

    default:
      warning (_("Cannot initialize thread debugging library: %s"),
	       td_err_string (err));
      break;
    }
}

/* This routine is called whenever a new symbol table is read in, or
   when all symbol tables are removed.  libthread_db can only be
   initialized when it finds the right variables in libthread.so.
   Since it's a shared library, those variables don't show up until
   the library gets mapped and the symbol table is read in.  */

static void
sol_thread_new_objfile (struct objfile *objfile)
{
  if (objfile != NULL)
    check_for_thread_db ();
}

/* Clean up after the inferior dies.  */

void
sol_thread_target::mourn_inferior ()
{
  target_ops *beneath = this->beneath ();

  sol_thread_active = 0;

  unpush_target (this);

  beneath->mourn_inferior ();
}

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

bool
sol_thread_target::thread_alive (ptid_t ptid)
{
  if (ptid.tid_p ())
    {
      /* It's a (user-level) thread.  */
      td_err_e val;
      td_thrhandle_t th;
      int pid;

      pid = ptid.tid ();
      val = p_td_ta_map_id2thr (main_ta, pid, &th);
      if (val != TD_OK)
	return false;		/* Thread not found.  */
      val = p_td_thr_validate (&th);
      if (val != TD_OK)
	return false;		/* Thread not valid.  */
      return true;		/* Known thread.  */
    }
  else
    {
      /* It's an LPW; pass the request on to the layer below.  */
      return beneath ()->thread_alive (ptid);
    }
}


/* These routines implement the lower half of the thread_db interface,
   i.e. the ps_* routines.  */

/* The next four routines are called by libthread_db to tell us to
   stop and stop a particular process or lwp.  Since GDB ensures that
   these are all stopped by the time we call anything in thread_db,
   these routines need to do nothing.  */

/* Process stop.  */

ps_err_e
ps_pstop (struct ps_prochandle *ph)
{
  return PS_OK;
}

/* Process continue.  */

ps_err_e
ps_pcontinue (struct ps_prochandle *ph)
{
  return PS_OK;
}

/* LWP stop.  */

ps_err_e
ps_lstop (struct ps_prochandle *ph, lwpid_t lwpid)
{
  return PS_OK;
}

/* LWP continue.  */

ps_err_e
ps_lcontinue (struct ps_prochandle *ph, lwpid_t lwpid)
{
  return PS_OK;
}

/* Looks up the symbol LD_SYMBOL_NAME in the debugger's symbol table.  */

ps_err_e
ps_pglobal_lookup (struct ps_prochandle *ph, const char *ld_object_name,
		   const char *ld_symbol_name, psaddr_t *ld_symbol_addr)
{
  struct bound_minimal_symbol ms;

  ms = lookup_minimal_symbol (ld_symbol_name, NULL, NULL);
  if (!ms.minsym)
    return PS_NOSYM;

  *ld_symbol_addr = BMSYMBOL_VALUE_ADDRESS (ms);
  return PS_OK;
}

/* Common routine for reading and writing memory.  */

static ps_err_e
rw_common (int dowrite, const struct ps_prochandle *ph, psaddr_t addr,
	   gdb_byte *buf, int size)
{
  int ret;

  scoped_restore save_inferior_ptid = make_scoped_restore (&inferior_ptid);

  if (inferior_ptid.tid_p () || !target_thread_alive (inferior_ptid))
    {
      /* It's either a thread or an LWP that isn't alive.  Any live
         LWP will do so use the first available.

	 NOTE: We don't need to call switch_to_thread; we're just
	 reading memory.  */
      inferior_ptid = procfs_first_available ();
    }

#if defined (__sparcv9)
  /* For Sparc64 cross Sparc32, make sure the address has not been
     accidentally sign-extended (or whatever) to beyond 32 bits.  */
  if (bfd_get_arch_size (exec_bfd) == 32)
    addr &= 0xffffffff;
#endif

  if (dowrite)
    ret = target_write_memory (addr, (gdb_byte *) buf, size);
  else
    ret = target_read_memory (addr, (gdb_byte *) buf, size);

  return (ret == 0 ? PS_OK : PS_ERR);
}

/* Copies SIZE bytes from target process .data segment to debugger memory.  */

ps_err_e
ps_pdread (struct ps_prochandle *ph, psaddr_t addr, void *buf, size_t size)
{
  return rw_common (0, ph, addr, (gdb_byte *) buf, size);
}

/* Copies SIZE bytes from debugger memory .data segment to target process.  */

ps_err_e
ps_pdwrite (struct ps_prochandle *ph, psaddr_t addr,
	    const void *buf, size_t size)
{
  return rw_common (1, ph, addr, (gdb_byte *) buf, size);
}

/* Copies SIZE bytes from target process .text segment to debugger memory.  */

ps_err_e
ps_ptread (struct ps_prochandle *ph, psaddr_t addr, void *buf, size_t size)
{
  return rw_common (0, ph, addr, (gdb_byte *) buf, size);
}

/* Copies SIZE bytes from debugger memory .text segment to target process.  */

ps_err_e
ps_ptwrite (struct ps_prochandle *ph, psaddr_t addr,
	    const void *buf, size_t size)
{
  return rw_common (1, ph, addr, (gdb_byte *) buf, size);
}

/* Get general-purpose registers for LWP.  */

ps_err_e
ps_lgetregs (struct ps_prochandle *ph, lwpid_t lwpid, prgregset_t gregset)
{
  ptid_t ptid = ptid_t (current_inferior ()->pid, lwpid, 0);
  struct regcache *regcache
    = get_thread_arch_regcache (current_inferior ()->process_target (),
				ptid, target_gdbarch ());

  target_fetch_registers (regcache, -1);
  fill_gregset (regcache, (gdb_gregset_t *) gregset, -1);

  return PS_OK;
}

/* Set general-purpose registers for LWP.  */

ps_err_e
ps_lsetregs (struct ps_prochandle *ph, lwpid_t lwpid,
	     const prgregset_t gregset)
{
  ptid_t ptid = ptid_t (current_inferior ()->pid, lwpid, 0);
  struct regcache *regcache
    = get_thread_arch_regcache (current_inferior ()->process_target (),
				ptid, target_gdbarch ());

  supply_gregset (regcache, (const gdb_gregset_t *) gregset);
  target_store_registers (regcache, -1);

  return PS_OK;
}

/* Log a message (sends to gdb_stderr).  */

void
ps_plog (const char *fmt, ...)
{
  va_list args;

  va_start (args, fmt);

  vfprintf_filtered (gdb_stderr, fmt, args);
}

/* Get size of extra register set.  Currently a noop.  */

ps_err_e
ps_lgetxregsize (struct ps_prochandle *ph, lwpid_t lwpid, int *xregsize)
{
  return PS_OK;
}

/* Get extra register set.  Currently a noop.  */

ps_err_e
ps_lgetxregs (struct ps_prochandle *ph, lwpid_t lwpid, caddr_t xregset)
{
  return PS_OK;
}

/* Set extra register set.  Currently a noop.  */

ps_err_e
ps_lsetxregs (struct ps_prochandle *ph, lwpid_t lwpid, caddr_t xregset)
{
  return PS_OK;
}

/* Get floating-point registers for LWP.  */

ps_err_e
ps_lgetfpregs (struct ps_prochandle *ph, lwpid_t lwpid,
	       prfpregset_t *fpregset)
{
  ptid_t ptid = ptid_t (current_inferior ()->pid, lwpid, 0);
  struct regcache *regcache
    = get_thread_arch_regcache (current_inferior ()->process_target (),
				ptid, target_gdbarch ());

  target_fetch_registers (regcache, -1);
  fill_fpregset (regcache, (gdb_fpregset_t *) fpregset, -1);

  return PS_OK;
}

/* Set floating-point regs for LWP.  */

ps_err_e
ps_lsetfpregs (struct ps_prochandle *ph, lwpid_t lwpid,
	       const prfpregset_t * fpregset)
{
  ptid_t ptid = ptid_t (current_inferior ()->pid, lwpid, 0);
  struct regcache *regcache
    = get_thread_arch_regcache (current_inferior ()->process_target (),
				ptid, target_gdbarch ());

  supply_fpregset (regcache, (const gdb_fpregset_t *) fpregset);
  target_store_registers (regcache, -1);

  return PS_OK;
}

/* Identify process as 32-bit or 64-bit.  At the moment we're using
   BFD to do this.  There might be a more Solaris-specific
   (e.g. procfs) method, but this ought to work.  */

ps_err_e
ps_pdmodel (struct ps_prochandle *ph, int *data_model)
{
  if (exec_bfd == 0)
    *data_model = PR_MODEL_UNKNOWN;
  else if (bfd_get_arch_size (exec_bfd) == 32)
    *data_model = PR_MODEL_ILP32;
  else
    *data_model = PR_MODEL_LP64;

  return PS_OK;
}


/* Convert PTID to printable form.  */

std::string
sol_thread_target::pid_to_str (ptid_t ptid)
{
  if (ptid.tid_p ())
    {
      ptid_t lwp;

      lwp = thread_to_lwp (ptid, -2);

      if (lwp.pid () == -1)
	return string_printf ("Thread %ld (defunct)",
			      ptid.tid ());
      else if (lwp.pid () != -2)
	return string_printf ("Thread %ld (LWP %ld)",
			      ptid.tid (), lwp.lwp ());
      else
	return string_printf ("Thread %ld        ",
			      ptid.tid ());
    }
  else if (ptid.lwp () != 0)
    return string_printf ("LWP    %ld        ", ptid.lwp ());
  else
    return string_printf ("process %d    ", ptid.pid ());
}


/* Worker bee for update_thread_list.  Callback function that gets
   called once per user-level thread (i.e. not for LWP's).  */

static int
sol_update_thread_list_callback (const td_thrhandle_t *th, void *ignored)
{
  td_err_e retval;
  td_thrinfo_t ti;

  retval = p_td_thr_get_info (th, &ti);
  if (retval != TD_OK)
    return -1;

  ptid_t ptid = ptid_t (current_inferior ()->pid, 0, ti.ti_tid);
  thread_info *thr = find_thread_ptid (current_inferior (), ptid);
  if (thr == NULL || thr->state == THREAD_EXITED)
    {
      process_stratum_target *proc_target
	= current_inferior ()->process_target ();
      add_thread (proc_target, ptid);
    }

  return 0;
}

void
sol_thread_target::update_thread_list ()
{
  /* Delete dead threads.  */
  prune_threads ();

  /* Find any new LWP's.  */
  beneath ()->update_thread_list ();

  /* Then find any new user-level threads.  */
  p_td_ta_thr_iter (main_ta, sol_update_thread_list_callback, (void *) 0,
		    TD_THR_ANY_STATE, TD_THR_LOWEST_PRIORITY,
		    TD_SIGNO_MASK, TD_THR_ANY_USER_FLAGS);
}

/* Worker bee for the "info sol-thread" command.  This is a callback
   function that gets called once for each Solaris user-level thread
   (i.e. not for LWPs) in the inferior.  Print anything interesting
   that we can think of.  */

static int
info_cb (const td_thrhandle_t *th, void *s)
{
  td_err_e ret;
  td_thrinfo_t ti;

  ret = p_td_thr_get_info (th, &ti);
  if (ret == TD_OK)
    {
      printf_filtered ("%s thread #%d, lwp %d, ",
		       ti.ti_type == TD_THR_SYSTEM ? "system" : "user  ",
		       ti.ti_tid, ti.ti_lid);
      switch (ti.ti_state)
	{
	default:
	case TD_THR_UNKNOWN:
	  printf_filtered ("<unknown state>");
	  break;
	case TD_THR_STOPPED:
	  printf_filtered ("(stopped)");
	  break;
	case TD_THR_RUN:
	  printf_filtered ("(run)    ");
	  break;
	case TD_THR_ACTIVE:
	  printf_filtered ("(active) ");
	  break;
	case TD_THR_ZOMBIE:
	  printf_filtered ("(zombie) ");
	  break;
	case TD_THR_SLEEP:
	  printf_filtered ("(asleep) ");
	  break;
	case TD_THR_STOPPED_ASLEEP:
	  printf_filtered ("(stopped asleep)");
	  break;
	}
      /* Print thr_create start function.  */
      if (ti.ti_startfunc != 0)
	{
	  const struct bound_minimal_symbol msym
	    = lookup_minimal_symbol_by_pc (ti.ti_startfunc);

	  printf_filtered ("   startfunc=%s",
			   msym.minsym
			   ? msym.minsym->print_name ()
			   : paddress (target_gdbarch (), ti.ti_startfunc));
	}

      /* If thread is asleep, print function that went to sleep.  */
      if (ti.ti_state == TD_THR_SLEEP)
	{
	  const struct bound_minimal_symbol msym
	    = lookup_minimal_symbol_by_pc (ti.ti_pc);

	  printf_filtered ("   sleepfunc=%s",
			   msym.minsym
			   ? msym.minsym->print_name ()
			   : paddress (target_gdbarch (), ti.ti_pc));
	}

      printf_filtered ("\n");
    }
  else
    warning (_("info sol-thread: failed to get info for thread."));

  return 0;
}

/* List some state about each Solaris user-level thread in the
   inferior.  */

static void
info_solthreads (const char *args, int from_tty)
{
  p_td_ta_thr_iter (main_ta, info_cb, (void *) args,
		    TD_THR_ANY_STATE, TD_THR_LOWEST_PRIORITY,
		    TD_SIGNO_MASK, TD_THR_ANY_USER_FLAGS);
}

/* Callback routine used to find a thread based on the TID part of
   its PTID.  */

static int
thread_db_find_thread_from_tid (struct thread_info *thread, void *data)
{
  long *tid = (long *) data;

  if (thread->ptid.tid () == *tid)
    return 1;

  return 0;
}

ptid_t
sol_thread_target::get_ada_task_ptid (long lwp, long thread)
{
  struct thread_info *thread_info =
    iterate_over_threads (thread_db_find_thread_from_tid, &thread);

  if (thread_info == NULL)
    {
      /* The list of threads is probably not up to date.  Find any
         thread that is missing from the list, and try again.  */
      update_thread_list ();
      thread_info = iterate_over_threads (thread_db_find_thread_from_tid,
                                          &thread);
    }

  gdb_assert (thread_info != NULL);

  return (thread_info->ptid);
}

void _initialize_sol_thread ();
void
_initialize_sol_thread ()
{
  void *dlhandle;

  dlhandle = dlopen ("libthread_db.so.1", RTLD_NOW);
  if (!dlhandle)
    goto die;

#define resolve(X) \
  if (!(p_##X = (X ## _ftype *) dlsym (dlhandle, #X)))	\
    goto die;

  resolve (td_log);
  resolve (td_ta_new);
  resolve (td_ta_delete);
  resolve (td_init);
  resolve (td_ta_get_ph);
  resolve (td_ta_get_nthreads);
  resolve (td_ta_tsd_iter);
  resolve (td_ta_thr_iter);
  resolve (td_thr_validate);
  resolve (td_thr_tsd);
  resolve (td_thr_get_info);
  resolve (td_thr_getfpregs);
  resolve (td_thr_getxregsize);
  resolve (td_thr_getxregs);
  resolve (td_thr_sigsetmask);
  resolve (td_thr_setprio);
  resolve (td_thr_setsigpending);
  resolve (td_thr_setfpregs);
  resolve (td_thr_setxregs);
  resolve (td_ta_map_id2thr);
  resolve (td_ta_map_lwp2thr);
  resolve (td_thr_getgregs);
  resolve (td_thr_setgregs);

  add_cmd ("sol-threads", class_maintenance, info_solthreads,
	   _("Show info on Solaris user threads."), &maintenanceinfolist);

  /* Hook into new_objfile notification.  */
  gdb::observers::new_objfile.attach (sol_thread_new_objfile);
  return;

 die:
  fprintf_unfiltered (gdb_stderr, "\
[GDB will not be able to debug user-mode threads: %s]\n", dlerror ());

  if (dlhandle)
    dlclose (dlhandle);

  return;
}