aboutsummaryrefslogtreecommitdiff
path: root/gdb/go32-nat.c
blob: 885662be76e624ce033872f5e3497744aed71f5f (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
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
/* Native debugging support for Intel x86 running DJGPP.
   Copyright 1997, 1999, 2001 Free Software Foundation, Inc.
   Written by Robert Hoehne.

   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 2 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, write to the Free Software
   Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */

#include <fcntl.h>

#include "defs.h"
#include "inferior.h"
#include "gdb_wait.h"
#include "gdbcore.h"
#include "command.h"
#include "floatformat.h"
#include "buildsym.h"

#include <stdio.h>		/* required for __DJGPP_MINOR__ */
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <io.h>
#include <dpmi.h>
#include <debug/v2load.h>
#include <debug/dbgcom.h>
#if __DJGPP_MINOR__ > 2
#include <debug/redir.h>
#endif

#if __DJGPP_MINOR__ < 3
/* This code will be provided from DJGPP 2.03 on. Until then I code it
   here */
typedef struct
  {
    unsigned short sig0;
    unsigned short sig1;
    unsigned short sig2;
    unsigned short sig3;
    unsigned short exponent:15;
    unsigned short sign:1;
  }
NPXREG;

typedef struct
  {
    unsigned int control;
    unsigned int status;
    unsigned int tag;
    unsigned int eip;
    unsigned int cs;
    unsigned int dataptr;
    unsigned int datasel;
    NPXREG reg[8];
  }
NPX;

static NPX npx;

static void save_npx (void);	/* Save the FPU of the debugged program */
static void load_npx (void);	/* Restore the FPU of the debugged program */

/* ------------------------------------------------------------------------- */
/* Store the contents of the NPX in the global variable `npx'.  */
/* *INDENT-OFF* */

static void
save_npx (void)
{
  asm ("inb    $0xa0, %%al
       testb $0x20, %%al
       jz 1f
       xorb %% al, %%al
       outb %% al, $0xf0
       movb $0x20, %%al
       outb %% al, $0xa0
       outb %% al, $0x20
1:
       fnsave % 0
       fwait "
:     "=m" (npx)
:				/* No input */
:     "%eax");
}

/* *INDENT-ON* */





/* ------------------------------------------------------------------------- */
/* Reload the contents of the NPX from the global variable `npx'.  */

static void
load_npx (void)
{
asm ("frstor %0":"=m" (npx));
}
/* ------------------------------------------------------------------------- */
/* Stubs for the missing redirection functions.  */
typedef struct {
  char *command;
  int redirected;
} cmdline_t;

void redir_cmdline_delete (cmdline_t *ptr) {ptr->redirected = 0;}
int  redir_cmdline_parse (const char *args, cmdline_t *ptr)
{
  return -1;
}
int redir_to_child (cmdline_t *ptr)
{
  return 1;
}
int redir_to_debugger (cmdline_t *ptr)
{
  return 1;
}
int redir_debug_init (cmdline_t *ptr) { return 0; }
#endif /* __DJGPP_MINOR < 3 */

extern void _initialize_go32_nat (void);

typedef enum { wp_insert, wp_remove, wp_count } wp_op;

/* This holds the current reference counts for each debug register.  */
static int dr_ref_count[4];

extern char **environ;

#define SOME_PID 42

static int prog_has_started = 0;
static void go32_open (char *name, int from_tty);
static void go32_close (int quitting);
static void go32_attach (char *args, int from_tty);
static void go32_detach (char *args, int from_tty);
static void go32_resume (int pid, int step, enum target_signal siggnal);
static int go32_wait (int pid, struct target_waitstatus *status);
static void go32_fetch_registers (int regno);
static void store_register (int regno);
static void go32_store_registers (int regno);
static void go32_prepare_to_store (void);
static int go32_xfer_memory (CORE_ADDR memaddr, char *myaddr, int len,
			     int write,
			     struct mem_attrib *attrib,
			     struct target_ops *target);
static void go32_files_info (struct target_ops *target);
static void go32_stop (void);
static void go32_kill_inferior (void);
static void go32_create_inferior (char *exec_file, char *args, char **env);
static void cleanup_dregs (void);
static void go32_mourn_inferior (void);
static int go32_can_run (void);
static int go32_insert_aligned_watchpoint (CORE_ADDR waddr, CORE_ADDR addr,
					   int len, int rw);
static int go32_remove_aligned_watchpoint (CORE_ADDR waddr, CORE_ADDR addr,
					   int len, int rw);
static int go32_handle_nonaligned_watchpoint (wp_op what, CORE_ADDR waddr,
					      CORE_ADDR addr, int len, int rw);

static struct target_ops go32_ops;
static void go32_terminal_init (void);
static void go32_terminal_inferior (void);
static void go32_terminal_ours (void);

#define r_ofs(x) (offsetof(TSS,x))

static struct
{
  size_t tss_ofs;
  size_t size;
}
regno_mapping[] =
{
  {r_ofs (tss_eax), 4},	/* normal registers, from a_tss */
  {r_ofs (tss_ecx), 4},
  {r_ofs (tss_edx), 4},
  {r_ofs (tss_ebx), 4},
  {r_ofs (tss_esp), 4},
  {r_ofs (tss_ebp), 4},
  {r_ofs (tss_esi), 4},
  {r_ofs (tss_edi), 4},
  {r_ofs (tss_eip), 4},
  {r_ofs (tss_eflags), 4},
  {r_ofs (tss_cs), 2},
  {r_ofs (tss_ss), 2},
  {r_ofs (tss_ds), 2},
  {r_ofs (tss_es), 2},
  {r_ofs (tss_fs), 2},
  {r_ofs (tss_gs), 2},
  {0, 10},		/* 8 FP registers, from npx.reg[] */
  {1, 10},
  {2, 10},
  {3, 10},
  {4, 10},
  {5, 10},
  {6, 10},
  {7, 10},
	/* The order of the next 7 registers must be consistent
	   with their numbering in config/i386/tm-i386.h, which see.  */
  {0, 2},		/* control word, from npx */
  {4, 2},		/* status word, from npx */
  {8, 2},		/* tag word, from npx */
  {16, 2},		/* last FP exception CS from npx */
  {12, 4},		/* last FP exception EIP from npx */
  {24, 2},		/* last FP exception operand selector from npx */
  {20, 4},		/* last FP exception operand offset from npx */
  {18, 2}		/* last FP opcode from npx */
};

static struct
  {
    int go32_sig;
    enum target_signal gdb_sig;
  }
sig_map[] =
{
  {0, TARGET_SIGNAL_FPE},
  {1, TARGET_SIGNAL_TRAP},
  /* Exception 2 is triggered by the NMI.  DJGPP handles it as SIGILL,
     but I think SIGBUS is better, since the NMI is usually activated
     as a result of a memory parity check failure.  */
  {2, TARGET_SIGNAL_BUS},
  {3, TARGET_SIGNAL_TRAP},
  {4, TARGET_SIGNAL_FPE},
  {5, TARGET_SIGNAL_SEGV},
  {6, TARGET_SIGNAL_ILL},
  {7, TARGET_SIGNAL_EMT},	/* no-coprocessor exception */
  {8, TARGET_SIGNAL_SEGV},
  {9, TARGET_SIGNAL_SEGV},
  {10, TARGET_SIGNAL_BUS},
  {11, TARGET_SIGNAL_SEGV},
  {12, TARGET_SIGNAL_SEGV},
  {13, TARGET_SIGNAL_SEGV},
  {14, TARGET_SIGNAL_SEGV},
  {16, TARGET_SIGNAL_FPE},
  {17, TARGET_SIGNAL_BUS},
  {31, TARGET_SIGNAL_ILL},
  {0x1b, TARGET_SIGNAL_INT},
  {0x75, TARGET_SIGNAL_FPE},
  {0x78, TARGET_SIGNAL_ALRM},
  {0x79, TARGET_SIGNAL_INT},
  {0x7a, TARGET_SIGNAL_QUIT},
  {-1, TARGET_SIGNAL_LAST}
};

static struct {
  enum target_signal gdb_sig;
  int djgpp_excepno;
} excepn_map[] = {
  {TARGET_SIGNAL_0, -1},
  {TARGET_SIGNAL_ILL, 6},	/* Invalid Opcode */
  {TARGET_SIGNAL_EMT, 7},	/* triggers SIGNOFP */
  {TARGET_SIGNAL_SEGV, 13},	/* GPF */
  {TARGET_SIGNAL_BUS, 17},	/* Alignment Check */
  /* The rest are fake exceptions, see dpmiexcp.c in djlsr*.zip for
     details.  */
  {TARGET_SIGNAL_TERM, 0x1b},	/* triggers Ctrl-Break type of SIGINT */
  {TARGET_SIGNAL_FPE, 0x75},
  {TARGET_SIGNAL_INT, 0x79},
  {TARGET_SIGNAL_QUIT, 0x7a},
  {TARGET_SIGNAL_ALRM, 0x78},	/* triggers SIGTIMR */
  {TARGET_SIGNAL_PROF, 0x78},
  {TARGET_SIGNAL_LAST, -1}
};

static void
go32_open (char *name ATTRIBUTE_UNUSED, int from_tty ATTRIBUTE_UNUSED)
{
  printf_unfiltered ("Done.  Use the \"run\" command to run the program.\n");
}

static void
go32_close (int quitting ATTRIBUTE_UNUSED)
{
}

static void
go32_attach (char *args ATTRIBUTE_UNUSED, int from_tty ATTRIBUTE_UNUSED)
{
  error ("\
You cannot attach to a running program on this platform.\n\
Use the `run' command to run DJGPP programs.");
}

static void
go32_detach (char *args ATTRIBUTE_UNUSED, int from_tty ATTRIBUTE_UNUSED)
{
}

static int resume_is_step;
static int resume_signal = -1;

static void
go32_resume (int pid ATTRIBUTE_UNUSED, int step, enum target_signal siggnal)
{
  int i;

  resume_is_step = step;

  if (siggnal != TARGET_SIGNAL_0 && siggnal != TARGET_SIGNAL_TRAP)
  {
    for (i = 0, resume_signal = -1;
	 excepn_map[i].gdb_sig != TARGET_SIGNAL_LAST; i++)
      if (excepn_map[i].gdb_sig == siggnal)
      {
	resume_signal = excepn_map[i].djgpp_excepno;
	break;
      }
    if (resume_signal == -1)
      printf_unfiltered ("Cannot deliver signal %s on this platform.\n",
			 target_signal_to_name (siggnal));
  }
}

static char child_cwd[FILENAME_MAX];

static int
go32_wait (int pid ATTRIBUTE_UNUSED, struct target_waitstatus *status)
{
  int i;
  unsigned char saved_opcode;
  unsigned long INT3_addr = 0;
  int stepping_over_INT = 0;

  a_tss.tss_eflags &= 0xfeff;	/* reset the single-step flag (TF) */
  if (resume_is_step)
    {
      /* If the next instruction is INT xx or INTO, we need to handle
	 them specially.  Intel manuals say that these instructions
	 reset the single-step flag (a.k.a. TF).  However, it seems
	 that, at least in the DPMI environment, and at least when
	 stepping over the DPMI interrupt 31h, the problem is having
	 TF set at all when INT 31h is executed: the debuggee either
	 crashes (and takes the system with it) or is killed by a
	 SIGTRAP.

	 So we need to emulate single-step mode: we put an INT3 opcode
	 right after the INT xx instruction, let the debuggee run
	 until it hits INT3 and stops, then restore the original
	 instruction which we overwrote with the INT3 opcode, and back
	 up the debuggee's EIP to that instruction.  */
      read_child (a_tss.tss_eip, &saved_opcode, 1);
      if (saved_opcode == 0xCD || saved_opcode == 0xCE)
	{
	  unsigned char INT3_opcode = 0xCC;

	  INT3_addr
	    = saved_opcode == 0xCD ? a_tss.tss_eip + 2 : a_tss.tss_eip + 1;
	  stepping_over_INT = 1;
	  read_child (INT3_addr, &saved_opcode, 1);
	  write_child (INT3_addr, &INT3_opcode, 1);
	}
      else
	a_tss.tss_eflags |= 0x0100; /* normal instruction: set TF */
    }

  /* The special value FFFFh in tss_trap indicates to run_child that
     tss_irqn holds a signal to be delivered to the debuggee.  */
  if (resume_signal <= -1)
    {
      a_tss.tss_trap = 0;
      a_tss.tss_irqn = 0xff;
    }
  else
    {
      a_tss.tss_trap = 0xffff;	/* run_child looks for this */
      a_tss.tss_irqn = resume_signal;
    }

  /* The child might change working directory behind our back.  The
     GDB users won't like the side effects of that when they work with
     relative file names, and GDB might be confused by its current
     directory not being in sync with the truth.  So we always make a
     point of changing back to where GDB thinks is its cwd, when we
     return control to the debugger, but restore child's cwd before we
     run it.  */
  /* Initialize child_cwd, before the first call to run_child and not
     in the initialization, so the child get also the changed directory
     set with the gdb-command "cd ..." */
  if (!*child_cwd)
    /* Initialize child's cwd with the current one.  */
    getcwd (child_cwd, sizeof (child_cwd));
    
  chdir (child_cwd);

#if __DJGPP_MINOR__ < 3
  load_npx ();
#endif
  run_child ();
#if __DJGPP_MINOR__ < 3
  save_npx ();
#endif

  /* Did we step over an INT xx instruction?  */
  if (stepping_over_INT && a_tss.tss_eip == INT3_addr + 1)
    {
      /* Restore the original opcode.  */
      a_tss.tss_eip--;	/* EIP points *after* the INT3 instruction */
      write_child (a_tss.tss_eip, &saved_opcode, 1);
      /* Simulate a TRAP exception.  */
      a_tss.tss_irqn = 1;
      a_tss.tss_eflags |= 0x0100;
    }

  getcwd (child_cwd, sizeof (child_cwd)); /* in case it has changed */
  chdir (current_directory);

  if (a_tss.tss_irqn == 0x21)
    {
      status->kind = TARGET_WAITKIND_EXITED;
      status->value.integer = a_tss.tss_eax & 0xff;
    }
  else
    {
      status->value.sig = TARGET_SIGNAL_UNKNOWN;
      status->kind = TARGET_WAITKIND_STOPPED;
      for (i = 0; sig_map[i].go32_sig != -1; i++)
	{
	  if (a_tss.tss_irqn == sig_map[i].go32_sig)
	    {
#if __DJGPP_MINOR__ < 3
	      if ((status->value.sig = sig_map[i].gdb_sig) !=
		  TARGET_SIGNAL_TRAP)
		status->kind = TARGET_WAITKIND_SIGNALLED;
#else
	      status->value.sig = sig_map[i].gdb_sig;
#endif
	      break;
	    }
	}
    }
  return SOME_PID;
}

static void
go32_fetch_registers (int regno)
{
  /*JHW */
  int end_reg = regno + 1;	/* just one reg initially */

  if (regno < 0)		/* do the all registers */
    {
      regno = 0;		/* start at first register */
      /* # regs in table */
      end_reg = sizeof (regno_mapping) / sizeof (regno_mapping[0]);
    }

  for (; regno < end_reg; regno++)
    {
      if (regno < 16)
	supply_register (regno,
			 (char *) &a_tss + regno_mapping[regno].tss_ofs);
      else if (regno < 24)
	supply_register (regno,
			 (char *) &npx.reg[regno_mapping[regno].tss_ofs]);
      else if (regno < 32)
	{
	  unsigned regval;

	  switch (regno_mapping[regno].size)
	    {
	      case 2:
		regval = *(unsigned short *)
		  ((char *) &npx + regno_mapping[regno].tss_ofs);
		regval &= 0xffff;
		if (regno == FOP_REGNUM && regval)
		  /* Feature: restore the 5 bits of the opcode
		     stripped by FSAVE/FNSAVE.  */
		  regval |= 0xd800;
		break;
	      case 4:
		regval = *(unsigned *)
		  ((char *) &npx + regno_mapping[regno].tss_ofs);
		break;
	      default:
		internal_error (__FILE__, __LINE__, "\
Invalid native size for register no. %d in go32_fetch_register.", regno);
	    }
	  supply_register (regno, (char *) &regval);
	}
      else
	internal_error (__FILE__, __LINE__,
			"Invalid register no. %d in go32_fetch_register.",
			regno);
    }
}

static void
store_register (int regno)
{
  void *rp;
  void *v = (void *) &registers[REGISTER_BYTE (regno)];

  if (regno < 16)
    rp = (char *) &a_tss + regno_mapping[regno].tss_ofs;
  else if (regno < 24)
    rp = (char *) &npx.reg[regno_mapping[regno].tss_ofs];
  else if (regno < 32)
    rp = (char *) &npx + regno_mapping[regno].tss_ofs;
  else
    internal_error (__FILE__, __LINE__,
		    "Invalid register no. %d in store_register.", regno);
  memcpy (rp, v, regno_mapping[regno].size);
  if (regno == FOP_REGNUM)
    *(short *)rp &= 0x07ff; /* strip high 5 bits, in case they added them */
}

static void
go32_store_registers (int regno)
{
  unsigned r;

  if (regno >= 0)
    store_register (regno);
  else
    {
      for (r = 0; r < sizeof (regno_mapping) / sizeof (regno_mapping[0]); r++)
	store_register (r);
    }
}

static void
go32_prepare_to_store (void)
{
}

static int
go32_xfer_memory (CORE_ADDR memaddr, char *myaddr, int len, int write,
		  struct mem_attrib *attrib ATTRIBUTE_UNUSED,
		  struct target_ops *target ATTRIBUTE_UNUSED)
{
  if (write)
    {
      if (write_child (memaddr, myaddr, len))
	{
	  return 0;
	}
      else
	{
	  return len;
	}
    }
  else
    {
      if (read_child (memaddr, myaddr, len))
	{
	  return 0;
	}
      else
	{
	  return len;
	}
    }
}

static cmdline_t child_cmd;	/* parsed child's command line kept here */

static void
go32_files_info (struct target_ops *target ATTRIBUTE_UNUSED)
{
  printf_unfiltered ("You are running a DJGPP V2 program.\n");
}

static void
go32_stop (void)
{
  normal_stop ();
  cleanup_client ();
  inferior_pid = 0;
  prog_has_started = 0;
}

static void
go32_kill_inferior (void)
{
  redir_cmdline_delete (&child_cmd);
  resume_signal = -1;
  resume_is_step = 0;
  unpush_target (&go32_ops);
}

static void
go32_create_inferior (char *exec_file, char *args, char **env)
{
  jmp_buf start_state;
  char *cmdline;
  char **env_save = environ;

  /* If no exec file handed to us, get it from the exec-file command -- with
     a good, common error message if none is specified.  */
  if (exec_file == 0)
    exec_file = get_exec_file (1);

  if (prog_has_started)
    {
      go32_stop ();
      go32_kill_inferior ();
    }
  resume_signal = -1;
  resume_is_step = 0;

  /* Initialize child's cwd as empty to be initialized when starting
     the child.  */
  *child_cwd = 0;

  /* Init command line storage.  */
  if (redir_debug_init (&child_cmd) == -1)
    internal_error (__FILE__, __LINE__,
		    "Cannot allocate redirection storage: not enough memory.\n");

  /* Parse the command line and create redirections.  */
  if (strpbrk (args, "<>"))
    {
      if (redir_cmdline_parse (args, &child_cmd) == 0)
	args = child_cmd.command;
      else
	error ("Syntax error in command line.");
    }
  else
    child_cmd.command = xstrdup (args);

  cmdline = (char *) alloca (strlen (args) + 4);
  cmdline[0] = strlen (args);
  strcpy (cmdline + 1, args);
  cmdline[strlen (args) + 1] = 13;

  environ = env;

  if (v2loadimage (exec_file, cmdline, start_state))
    {
      environ = env_save;
      printf_unfiltered ("Load failed for image %s\n", exec_file);
      exit (1);
    }
  environ = env_save;

  edi_init (start_state);
#if __DJGPP_MINOR__ < 3
  save_npx ();
#endif

  inferior_pid = SOME_PID;
  push_target (&go32_ops);
  clear_proceed_status ();
  insert_breakpoints ();
  proceed ((CORE_ADDR) -1, TARGET_SIGNAL_0, 0);
  prog_has_started = 1;
}

static void
go32_mourn_inferior (void)
{
  /* We need to make sure all the breakpoint enable bits in the DR7
     register are reset when the inferior exits.  Otherwise, if they
     rerun the inferior, the uncleared bits may cause random SIGTRAPs,
     failure to set more watchpoints, and other calamities.  It would
     be nice if GDB itself would take care to remove all breakpoints
     at all times, but it doesn't, probably under an assumption that
     the OS cleans up when the debuggee exits.  */
  cleanup_dregs ();
  go32_kill_inferior ();
  generic_mourn_inferior ();
}

static int
go32_can_run (void)
{
  return 1;
}

/* Hardware watchpoint support.  */

#define DR_STATUS 6
#define DR_CONTROL 7
#define DR_ENABLE_SIZE 2
#define DR_LOCAL_ENABLE_SHIFT 0
#define DR_GLOBAL_ENABLE_SHIFT 1
#define DR_LOCAL_SLOWDOWN 0x100
#define DR_GLOBAL_SLOWDOWN 0x200
#define DR_CONTROL_SHIFT 16
#define DR_CONTROL_SIZE 4
#define DR_RW_READWRITE 0x3
#define DR_RW_WRITE 0x1
#define DR_CONTROL_MASK 0xf
#define DR_ENABLE_MASK 0x3
#define DR_LEN_1 0x0
#define DR_LEN_2 0x4
#define DR_LEN_4 0xc

#define D_REGS edi.dr
#define CONTROL D_REGS[DR_CONTROL]
#define STATUS D_REGS[DR_STATUS]

#define IS_REG_FREE(index) \
  (!(CONTROL & (3 << (DR_ENABLE_SIZE * (index)))))

#define LOCAL_ENABLE_REG(index) \
  (CONTROL |= (1 << (DR_LOCAL_ENABLE_SHIFT + DR_ENABLE_SIZE * (index))))

#define GLOBAL_ENABLE_REG(index) \
  (CONTROL |= (1 << (DR_GLOBAL_ENABLE_SHIFT + DR_ENABLE_SIZE * (index))))

#define DISABLE_REG(index) \
  (CONTROL &= ~(3 << (DR_ENABLE_SIZE * (index))))

#define SET_LOCAL_EXACT() \
  (CONTROL |= DR_LOCAL_SLOWDOWN)

#define SET_GLOBAL_EXACT() \
  (CONTROL |= DR_GLOBAL_SLOWDOWN)

#define RESET_LOCAL_EXACT() \
   (CONTROL &= ~(DR_LOCAL_SLOWDOWN))

#define RESET_GLOBAL_EXACT() \
   (CONTROL &= ~(DR_GLOBAL_SLOWDOWN))

#define SET_BREAK(index,address) \
  do {\
    CONTROL &= ~(DR_CONTROL_MASK << (DR_CONTROL_SHIFT + DR_CONTROL_SIZE * (index)));\
    D_REGS[index] = address;\
    dr_ref_count[index]++;\
  } while(0)

#define SET_WATCH(index,address,rw,len) \
  do {\
    SET_BREAK(index,address);\
    CONTROL |= ((len)|(rw)) << (DR_CONTROL_SHIFT + DR_CONTROL_SIZE * (index));\
  } while (0)

#define IS_WATCH(index) \
  (CONTROL & (DR_CONTROL_MASK << (DR_CONTROL_SHIFT + DR_CONTROL_SIZE*(index))))

#define WATCH_HIT(index) ((STATUS & (1 << (index))) && IS_WATCH(index))

#define DR_DEF(index) \
  ((CONTROL >> (DR_CONTROL_SHIFT + DR_CONTROL_SIZE * (index))) & 0x0f)
    

#if 0 /* use debugging macro */
#define SHOW_DR(text,len) \
do { \
  if (!getenv ("GDB_SHOW_DR")) break; \
  fprintf(stderr,"%08x %08x ",edi.dr[7],edi.dr[6]); \
  fprintf(stderr,"%08x %d %08x %d ", \
	  edi.dr[0],dr_ref_count[0],edi.dr[1],dr_ref_count[1]); \
  fprintf(stderr,"%08x %d %08x %d ", \
	  edi.dr[2],dr_ref_count[2],edi.dr[3],dr_ref_count[3]); \
  fprintf(stderr,(len)?"(%s:%d)\n":"(%s)\n",#text,len); \
} while (0)
#else
#define SHOW_DR(text,len) do {} while (0)
#endif

static void
cleanup_dregs (void)
{
  int i;

  CONTROL = 0;
  STATUS = 0;
  for (i = 0; i < 4; i++)
    {
      D_REGS[i] = 0;
      dr_ref_count[i] = 0;
    }
}

/* Insert a watchpoint.  */

int
go32_insert_watchpoint (int pid ATTRIBUTE_UNUSED, CORE_ADDR addr,
			int len, int rw)
{
  int ret = go32_insert_aligned_watchpoint (addr, addr, len, rw);

  SHOW_DR (insert_watch, len);
  return ret;
}

static int
go32_insert_aligned_watchpoint (CORE_ADDR waddr, CORE_ADDR addr,
				int len, int rw)
{
  int i;
  int read_write_bits, len_bits;

  /* Values of rw: 0 - write, 1 - read, 2 - access (read and write).
     However, x86 doesn't support read-only data breakpoints.  */
  read_write_bits = rw ? DR_RW_READWRITE : DR_RW_WRITE;

  switch (len)
  {
  case 4:
    len_bits = DR_LEN_4;
    break;
  case 2:
    len_bits = DR_LEN_2;
    break;
  case 1:
    len_bits = DR_LEN_1;
    break;
  default:
    /* The debug registers only have 2 bits for the length, so
       so this value will always fail the loop below.  */
    len_bits = 0x10;
  }

  /* Look for an occupied debug register with the same address and the
     same RW and LEN definitions.  If we find one, we can use it for
     this watchpoint as well (and save a register).  */
  for (i = 0; i < 4; i++)
  {
    if (!IS_REG_FREE (i) && D_REGS[i] == addr
	&& DR_DEF (i) == (unsigned)(len_bits | read_write_bits))
    {
      dr_ref_count[i]++;
      return 0;
    }
  }

  /* Look for a free debug register.  */
  for (i = 0; i <= 3; i++)
  {
    if (IS_REG_FREE (i))
      break;
  }

  /* No more debug registers!  */
  if (i > 3)
    return -1;

  if (len == 2)
  {
    if (addr % 2)
      return go32_handle_nonaligned_watchpoint (wp_insert, waddr, addr,
						len, rw);
  }
  else if (len == 4)
  {
    if (addr % 4)
      return go32_handle_nonaligned_watchpoint (wp_insert, waddr, addr,
						len, rw);
  }
  else if (len != 1)
    return go32_handle_nonaligned_watchpoint (wp_insert, waddr, addr, len, rw);

  SET_WATCH (i, addr, read_write_bits, len_bits);
  LOCAL_ENABLE_REG (i);
  SET_LOCAL_EXACT ();
  SET_GLOBAL_EXACT ();
  return 0;
}

static int
go32_handle_nonaligned_watchpoint (wp_op what, CORE_ADDR waddr, CORE_ADDR addr,
				   int len, int rw)
{
  int align;
  int size;
  int rv = 0, status = 0;

  static int size_try_array[4][4] =
  {
    { 1, 1, 1, 1 },		/* trying size one */
    { 2, 1, 2, 1 },		/* trying size two */
    { 2, 1, 2, 1 },		/* trying size three */
    { 4, 1, 2, 1 }		/* trying size four */
  };

  while (len > 0)
    {
      align = addr % 4;
      /* Four is the maximum length a 386 debug register can watch.  */
      size = size_try_array[len > 4 ? 3 : len - 1][align];
      if (what == wp_insert)
	status = go32_insert_aligned_watchpoint (waddr, addr, size, rw);
      else if (what == wp_remove)
	status = go32_remove_aligned_watchpoint (waddr, addr, size, rw);
      else if (what == wp_count)
	rv++;
      else
	status = EINVAL;
      /* We keep the loop going even after a failure, because some of
	 the other aligned watchpoints might still succeed, e.g. if
	 they watch addresses that are already watched, and thus just
	 increment the reference counts of occupied debug registers.
	 If we break out of the loop too early, we could cause those
	 addresses watched by other watchpoints to be disabled when
	 GDB reacts to our failure to insert this watchpoint and tries
	 to remove it.  */
      if (status)
	rv = status;
      addr += size;
      len -= size;
    }
  return rv;
}

/* Remove a watchpoint.  */

int
go32_remove_watchpoint (int pid ATTRIBUTE_UNUSED, CORE_ADDR addr,
			int len, int rw)
{
  int ret = go32_remove_aligned_watchpoint (addr, addr, len, rw);

  SHOW_DR (remove_watch, len);
  return ret;
}

static int
go32_remove_aligned_watchpoint (CORE_ADDR waddr, CORE_ADDR addr,
				int len, int rw)
{
  int i;
  int read_write_bits, len_bits;

  /* Values of rw: 0 - write, 1 - read, 2 - access (read and write).
     However, x86 doesn't support read-only data breakpoints.  */
  read_write_bits = rw ? DR_RW_READWRITE : DR_RW_WRITE;

  switch (len)
    {
      case 4:
	len_bits = DR_LEN_4;
	break;
      case 2:
	len_bits = DR_LEN_2;
	break;
      case 1:
	len_bits = DR_LEN_1;
	break;
      default:
	/* The debug registers only have 2 bits for the length, so
	   so this value will always fail the loop below.  */
	len_bits = 0x10;
    }

  if (len == 2)
    {
      if (addr % 2)
	return go32_handle_nonaligned_watchpoint (wp_remove, waddr, addr,
						  len, rw);
    }
  else if (len == 4)
    {
      if (addr % 4)
	return go32_handle_nonaligned_watchpoint (wp_remove, waddr, addr,
						  len, rw);
    }
  else if (len != 1)
    return go32_handle_nonaligned_watchpoint (wp_remove, waddr, addr, len, rw);

  for (i = 0; i <= 3; i++)
    {
      if (!IS_REG_FREE (i) && D_REGS[i] == addr
	  && DR_DEF (i) == (unsigned)(len_bits | read_write_bits))
	{
	  dr_ref_count[i]--;
	  if (dr_ref_count[i] == 0)
	    DISABLE_REG (i);
	}
    }
  RESET_LOCAL_EXACT ();
  RESET_GLOBAL_EXACT ();

  return 0;
}

/* Can we use debug registers to watch a region whose address is ADDR
   and whose length is LEN bytes?  */

int
go32_region_ok_for_watchpoint (CORE_ADDR addr, int len)
{
  /* Compute how many aligned watchpoints we would need to cover this
     region.  */
  int nregs = go32_handle_nonaligned_watchpoint (wp_count, addr, addr, len, 0);

  return nregs <= 4 ? 1 : 0;
}

/* Check if stopped by a data watchpoint.  If so, return the address
   whose access triggered the watchpoint.  */

CORE_ADDR
go32_stopped_by_watchpoint (int pid ATTRIBUTE_UNUSED, int data_watchpoint)
{
  int i, ret = 0;
  int status;

  status = edi.dr[DR_STATUS];
  SHOW_DR (stopped_by, 0);
  for (i = 0; i <= 3; i++)
    {
      if (WATCH_HIT (i) && data_watchpoint)
	{
	  SHOW_DR (WP_HIT, 0);
	  ret = D_REGS[i];
	}
    }

  return ret;
}

/* Remove a breakpoint.  */

int
go32_remove_hw_breakpoint (CORE_ADDR addr, void *shadow ATTRIBUTE_UNUSED)
{
  int i;
  for (i = 0; i <= 3; i++)
    {
      if (!IS_REG_FREE (i) && D_REGS[i] == addr && DR_DEF (i) == 0)
	{
	  dr_ref_count[i]--;
	  if (dr_ref_count[i] == 0)
	    DISABLE_REG (i);
	}
    }
  SHOW_DR (remove_hw, 0);
  return 0;
}

int
go32_insert_hw_breakpoint (CORE_ADDR addr, void *shadow ATTRIBUTE_UNUSED)
{
  int i;

  /* Look for an occupied debug register with the same address and the
     same RW and LEN definitions.  If we find one, we can use it for
     this breakpoint as well (and save a register).  */
  for (i = 0; i < 4; i++)
    {
      if (!IS_REG_FREE (i) && D_REGS[i] == addr && DR_DEF (i) == 0)
	{
	  dr_ref_count[i]++;
	  SHOW_DR (insert_hw, 0);
	  return 0;
	}
    }

  /* Look for a free debug register.  */
  for (i = 0; i <= 3; i++)
    {
      if (IS_REG_FREE (i))
	break;
    }

  /* No more debug registers?  */
  if (i < 4)
    {
      SET_BREAK (i, addr);
      LOCAL_ENABLE_REG (i);
    }
  SHOW_DR (insert_hw, 0);

  return i < 4 ? 0 : EBUSY;
}

/* Put the device open on handle FD into either raw or cooked
   mode, return 1 if it was in raw mode, zero otherwise.  */

static int
device_mode (int fd, int raw_p)
{
  int oldmode, newmode;
  __dpmi_regs regs;

  regs.x.ax = 0x4400;
  regs.x.bx = fd;
  __dpmi_int (0x21, &regs);
  if (regs.x.flags & 1)
    return -1;
  newmode = oldmode = regs.x.dx;

  if (raw_p)
    newmode |= 0x20;
  else
    newmode &= ~0x20;

  if (oldmode & 0x80)	/* Only for character dev */
  {
    regs.x.ax = 0x4401;
    regs.x.bx = fd;
    regs.x.dx = newmode & 0xff;   /* Force upper byte zero, else it fails */
    __dpmi_int (0x21, &regs);
    if (regs.x.flags & 1)
      return -1;
  }
  return (oldmode & 0x20) == 0x20;
}


static int inf_mode_valid = 0;
static int inf_terminal_mode;

/* This semaphore is needed because, amazingly enough, GDB calls
   target.to_terminal_ours more than once after the inferior stops.
   But we need the information from the first call only, since the
   second call will always see GDB's own cooked terminal.  */
static int terminal_is_ours = 1;

static void
go32_terminal_init (void)
{
  inf_mode_valid = 0;	/* reinitialize, in case they are restarting child */
  terminal_is_ours = 1;
}

static void
go32_terminal_info (char *args ATTRIBUTE_UNUSED, int from_tty ATTRIBUTE_UNUSED)
{
  printf_unfiltered ("Inferior's terminal is in %s mode.\n",
		     !inf_mode_valid
		     ? "default" : inf_terminal_mode ? "raw" : "cooked");

#if __DJGPP_MINOR__ > 2
  if (child_cmd.redirection)
  {
    int i;

    for (i = 0; i < DBG_HANDLES; i++)
    {
      if (child_cmd.redirection[i]->file_name)
	printf_unfiltered ("\tFile handle %d is redirected to `%s'.\n",
			   i, child_cmd.redirection[i]->file_name);
      else if (_get_dev_info (child_cmd.redirection[i]->inf_handle) == -1)
	printf_unfiltered
	  ("\tFile handle %d appears to be closed by inferior.\n", i);
      /* Mask off the raw/cooked bit when comparing device info words.  */
      else if ((_get_dev_info (child_cmd.redirection[i]->inf_handle) & 0xdf)
	       != (_get_dev_info (i) & 0xdf))
	printf_unfiltered
	  ("\tFile handle %d appears to be redirected by inferior.\n", i);
    }
  }
#endif
}

static void
go32_terminal_inferior (void)
{
  /* Redirect standard handles as child wants them.  */
  errno = 0;
  if (redir_to_child (&child_cmd) == -1)
  {
    redir_to_debugger (&child_cmd);
    error ("Cannot redirect standard handles for program: %s.",
	   strerror (errno));
  }
  /* set the console device of the inferior to whatever mode
     (raw or cooked) we found it last time */
  if (terminal_is_ours)
  {
    if (inf_mode_valid)
      device_mode (0, inf_terminal_mode);
    terminal_is_ours = 0;
  }
}

static void
go32_terminal_ours (void)
{
  /* Switch to cooked mode on the gdb terminal and save the inferior
     terminal mode to be restored when it is resumed */
  if (!terminal_is_ours)
  {
    inf_terminal_mode = device_mode (0, 0);
    if (inf_terminal_mode != -1)
      inf_mode_valid = 1;
    else
      /* If device_mode returned -1, we don't know what happens with
	 handle 0 anymore, so make the info invalid.  */
      inf_mode_valid = 0;
    terminal_is_ours = 1;

    /* Restore debugger's standard handles.  */
    errno = 0;
    if (redir_to_debugger (&child_cmd) == -1)
    {
      redir_to_child (&child_cmd);
      error ("Cannot redirect standard handles for debugger: %s.",
	     strerror (errno));
    }
  }
}

static void
init_go32_ops (void)
{
  go32_ops.to_shortname = "djgpp";
  go32_ops.to_longname = "djgpp target process";
  go32_ops.to_doc =
    "Program loaded by djgpp, when gdb is used as an external debugger";
  go32_ops.to_open = go32_open;
  go32_ops.to_close = go32_close;
  go32_ops.to_attach = go32_attach;
  go32_ops.to_detach = go32_detach;
  go32_ops.to_resume = go32_resume;
  go32_ops.to_wait = go32_wait;
  go32_ops.to_fetch_registers = go32_fetch_registers;
  go32_ops.to_store_registers = go32_store_registers;
  go32_ops.to_prepare_to_store = go32_prepare_to_store;
  go32_ops.to_xfer_memory = go32_xfer_memory;
  go32_ops.to_files_info = go32_files_info;
  go32_ops.to_insert_breakpoint = memory_insert_breakpoint;
  go32_ops.to_remove_breakpoint = memory_remove_breakpoint;
  go32_ops.to_terminal_init = go32_terminal_init;
  go32_ops.to_terminal_inferior = go32_terminal_inferior;
  go32_ops.to_terminal_ours_for_output = go32_terminal_ours;
  go32_ops.to_terminal_ours = go32_terminal_ours;
  go32_ops.to_terminal_info = go32_terminal_info;
  go32_ops.to_kill = go32_kill_inferior;
  go32_ops.to_create_inferior = go32_create_inferior;
  go32_ops.to_mourn_inferior = go32_mourn_inferior;
  go32_ops.to_can_run = go32_can_run;
  go32_ops.to_stop = go32_stop;
  go32_ops.to_stratum = process_stratum;
  go32_ops.to_has_all_memory = 1;
  go32_ops.to_has_memory = 1;
  go32_ops.to_has_stack = 1;
  go32_ops.to_has_registers = 1;
  go32_ops.to_has_execution = 1;
  go32_ops.to_magic = OPS_MAGIC;

  /* Initialize child's cwd as empty to be initialized when starting
     the child.  */
  *child_cwd = 0;

  /* Initialize child's command line storage.  */
  if (redir_debug_init (&child_cmd) == -1)
    internal_error (__FILE__, __LINE__,
		    "Cannot allocate redirection storage: not enough memory.\n");

  /* We are always processing GCC-compiled programs.  */
  processing_gcc_compilation = 2;
}

void
_initialize_go32_nat (void)
{
  init_go32_ops ();
  add_target (&go32_ops);
}

pid_t
tcgetpgrp (int fd)
{
  if (isatty (fd))
    return SOME_PID;
  errno = ENOTTY;
  return -1;
}

int
tcsetpgrp (int fd, pid_t pgid)
{
  if (isatty (fd) && pgid == SOME_PID)
    return 0;
  errno = pgid == SOME_PID ? ENOTTY : ENOSYS;
  return -1;
}