summaryrefslogtreecommitdiffstats
path: root/src/core/gdbstub/gdbstub.cpp
blob: cfaf20a880e13ab720e037c3cddf979fd9ffd12d (plain) (blame)
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
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
// Copyright 2013 Dolphin Emulator Project
// Licensed under GPLv2+
// Refer to the license.txt file included.

// Originally written by Sven Peter <sven@fail0verflow.com> for anergistic.

#include <algorithm>
#include <atomic>
#include <climits>
#include <csignal>
#include <cstdarg>
#include <cstdio>
#include <cstring>
#include <map>
#include <numeric>
#include <fcntl.h>

#ifdef _WIN32
#include <winsock2.h>
// winsock2.h needs to be included first to prevent winsock.h being included by other includes
#include <io.h>
#include <iphlpapi.h>
#include <ws2tcpip.h>
#define SHUT_RDWR 2
#else
#include <netinet/in.h>
#include <sys/select.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <unistd.h>
#endif

#include "common/logging/log.h"
#include "common/string_util.h"
#include "common/swap.h"
#include "core/arm/arm_interface.h"
#include "core/core.h"
#include "core/core_cpu.h"
#include "core/gdbstub/gdbstub.h"
#include "core/hle/kernel/scheduler.h"
#include "core/loader/loader.h"
#include "core/memory.h"

namespace GDBStub {
namespace {
constexpr int GDB_BUFFER_SIZE = 10000;

constexpr char GDB_STUB_START = '$';
constexpr char GDB_STUB_END = '#';
constexpr char GDB_STUB_ACK = '+';
constexpr char GDB_STUB_NACK = '-';

#ifndef SIGTRAP
constexpr u32 SIGTRAP = 5;
#endif

#ifndef SIGTERM
constexpr u32 SIGTERM = 15;
#endif

#ifndef MSG_WAITALL
constexpr u32 MSG_WAITALL = 8;
#endif

constexpr u32 LR_REGISTER = 30;
constexpr u32 SP_REGISTER = 31;
constexpr u32 PC_REGISTER = 32;
constexpr u32 CPSR_REGISTER = 33;
constexpr u32 UC_ARM64_REG_Q0 = 34;
constexpr u32 FPSCR_REGISTER = 66;

// TODO/WiP - Used while working on support for FPU
constexpr u32 TODO_DUMMY_REG_997 = 997;
constexpr u32 TODO_DUMMY_REG_998 = 998;

// For sample XML files see the GDB source /gdb/features
// GDB also wants the l character at the start
// This XML defines what the registers are for this specific ARM device
constexpr char target_xml[] =
    R"(l<?xml version="1.0"?>
<!DOCTYPE target SYSTEM "gdb-target.dtd">
<target version="1.0">
  <feature name="org.gnu.gdb.aarch64.core">
    <reg name="x0" bitsize="64"/>
    <reg name="x1" bitsize="64"/>
    <reg name="x2" bitsize="64"/>
    <reg name="x3" bitsize="64"/>
    <reg name="x4" bitsize="64"/>
    <reg name="x5" bitsize="64"/>
    <reg name="x6" bitsize="64"/>
    <reg name="x7" bitsize="64"/>
    <reg name="x8" bitsize="64"/>
    <reg name="x9" bitsize="64"/>
    <reg name="x10" bitsize="64"/>
    <reg name="x11" bitsize="64"/>
    <reg name="x12" bitsize="64"/>
    <reg name="x13" bitsize="64"/>
    <reg name="x14" bitsize="64"/>
    <reg name="x15" bitsize="64"/>
    <reg name="x16" bitsize="64"/>
    <reg name="x17" bitsize="64"/>
    <reg name="x18" bitsize="64"/>
    <reg name="x19" bitsize="64"/>
    <reg name="x20" bitsize="64"/>
    <reg name="x21" bitsize="64"/>
    <reg name="x22" bitsize="64"/>
    <reg name="x23" bitsize="64"/>
    <reg name="x24" bitsize="64"/>
    <reg name="x25" bitsize="64"/>
    <reg name="x26" bitsize="64"/>
    <reg name="x27" bitsize="64"/>
    <reg name="x28" bitsize="64"/>
    <reg name="x29" bitsize="64"/>
    <reg name="x30" bitsize="64"/>
    <reg name="sp" bitsize="64" type="data_ptr"/>

    <reg name="pc" bitsize="64" type="code_ptr"/>

    <flags id="cpsr_flags" size="4">
      <field name="SP" start="0" end="0"/>
      <field name="" start="1" end="1"/>
      <field name="EL" start="2" end="3"/>
      <field name="nRW" start="4" end="4"/>
      <field name="" start="5" end="5"/>
      <field name="F" start="6" end="6"/>
      <field name="I" start="7" end="7"/>
      <field name="A" start="8" end="8"/>
      <field name="D" start="9" end="9"/>

      <field name="IL" start="20" end="20"/>
      <field name="SS" start="21" end="21"/>

      <field name="V" start="28" end="28"/>
      <field name="C" start="29" end="29"/>
      <field name="Z" start="30" end="30"/>
      <field name="N" start="31" end="31"/>
    </flags>
    <reg name="cpsr" bitsize="32" type="cpsr_flags"/>
  </feature>
  <feature name="org.gnu.gdb.aarch64.fpu">
  </feature>
</target>
)";

int gdbserver_socket = -1;

u8 command_buffer[GDB_BUFFER_SIZE];
u32 command_length;

u32 latest_signal = 0;
bool memory_break = false;

Kernel::Thread* current_thread = nullptr;
u32 current_core = 0;

// Binding to a port within the reserved ports range (0-1023) requires root permissions,
// so default to a port outside of that range.
u16 gdbstub_port = 24689;

bool halt_loop = true;
bool step_loop = false;
bool send_trap = false;

// If set to false, the server will never be started and no
// gdbstub-related functions will be executed.
std::atomic<bool> server_enabled(false);

#ifdef _WIN32
WSADATA InitData;
#endif

struct Breakpoint {
    bool active;
    VAddr addr;
    u64 len;
    std::array<u8, 4> inst;
};

using BreakpointMap = std::map<VAddr, Breakpoint>;
BreakpointMap breakpoints_execute;
BreakpointMap breakpoints_read;
BreakpointMap breakpoints_write;

struct Module {
    std::string name;
    VAddr beg;
    VAddr end;
};

std::vector<Module> modules;
} // Anonymous namespace

void RegisterModule(std::string name, VAddr beg, VAddr end, bool add_elf_ext) {
    Module module;
    if (add_elf_ext) {
        Common::SplitPath(name, nullptr, &module.name, nullptr);
        module.name += ".elf";
    } else {
        module.name = std::move(name);
    }
    module.beg = beg;
    module.end = end;
    modules.push_back(std::move(module));
}

static Kernel::Thread* FindThreadById(int id) {
    for (u32 core = 0; core < Core::NUM_CPU_CORES; core++) {
        const auto& threads = Core::System::GetInstance().Scheduler(core)->GetThreadList();
        for (auto& thread : threads) {
            if (thread->GetThreadId() == static_cast<u32>(id)) {
                current_core = core;
                return thread.get();
            }
        }
    }
    return nullptr;
}

static u64 RegRead(std::size_t id, Kernel::Thread* thread = nullptr) {
    if (!thread) {
        return 0;
    }

    if (id < SP_REGISTER) {
        return thread->context.cpu_registers[id];
    } else if (id == SP_REGISTER) {
        return thread->context.sp;
    } else if (id == PC_REGISTER) {
        return thread->context.pc;
    } else if (id == CPSR_REGISTER) {
        return thread->context.cpsr;
    } else if (id > CPSR_REGISTER && id < FPSCR_REGISTER) {
        return thread->context.fpu_registers[id - UC_ARM64_REG_Q0][0];
    } else {
        return 0;
    }
}

static void RegWrite(std::size_t id, u64 val, Kernel::Thread* thread = nullptr) {
    if (!thread) {
        return;
    }

    if (id < SP_REGISTER) {
        thread->context.cpu_registers[id] = val;
    } else if (id == SP_REGISTER) {
        thread->context.sp = val;
    } else if (id == PC_REGISTER) {
        thread->context.pc = val;
    } else if (id == CPSR_REGISTER) {
        thread->context.cpsr = val;
    } else if (id > CPSR_REGISTER && id < FPSCR_REGISTER) {
        thread->context.fpu_registers[id - (CPSR_REGISTER + 1)][0] = val;
    }
}

/**
 * Turns hex string character into the equivalent byte.
 *
 * @param hex Input hex character to be turned into byte.
 */
static u8 HexCharToValue(u8 hex) {
    if (hex >= '0' && hex <= '9') {
        return hex - '0';
    } else if (hex >= 'a' && hex <= 'f') {
        return hex - 'a' + 0xA;
    } else if (hex >= 'A' && hex <= 'F') {
        return hex - 'A' + 0xA;
    }

    LOG_ERROR(Debug_GDBStub, "Invalid nibble: {} ({:02X})", hex, hex);
    return 0;
}

/**
 * Turn nibble of byte into hex string character.
 *
 * @param n Nibble to be turned into hex character.
 */
static u8 NibbleToHex(u8 n) {
    n &= 0xF;
    if (n < 0xA) {
        return '0' + n;
    } else {
        return 'a' + n - 0xA;
    }
}

/**
 * Converts input hex string characters into an array of equivalent of u8 bytes.
 *
 * @param src Pointer to array of output hex string characters.
 * @param len Length of src array.
 */
static u32 HexToInt(const u8* src, std::size_t len) {
    u32 output = 0;
    while (len-- > 0) {
        output = (output << 4) | HexCharToValue(src[0]);
        src++;
    }
    return output;
}

/**
 * Converts input hex string characters into an array of equivalent of u8 bytes.
 *
 * @param src Pointer to array of output hex string characters.
 * @param len Length of src array.
 */
static u64 HexToLong(const u8* src, std::size_t len) {
    u64 output = 0;
    while (len-- > 0) {
        output = (output << 4) | HexCharToValue(src[0]);
        src++;
    }
    return output;
}

/**
 * Converts input array of u8 bytes into their equivalent hex string characters.
 *
 * @param dest Pointer to buffer to store output hex string characters.
 * @param src Pointer to array of u8 bytes.
 * @param len Length of src array.
 */
static void MemToGdbHex(u8* dest, const u8* src, std::size_t len) {
    while (len-- > 0) {
        u8 tmp = *src++;
        *dest++ = NibbleToHex(tmp >> 4);
        *dest++ = NibbleToHex(tmp);
    }
}

/**
 * Converts input gdb-formatted hex string characters into an array of equivalent of u8 bytes.
 *
 * @param dest Pointer to buffer to store u8 bytes.
 * @param src Pointer to array of output hex string characters.
 * @param len Length of src array.
 */
static void GdbHexToMem(u8* dest, const u8* src, std::size_t len) {
    while (len-- > 0) {
        *dest++ = (HexCharToValue(src[0]) << 4) | HexCharToValue(src[1]);
        src += 2;
    }
}

/**
 * Convert a u32 into a gdb-formatted hex string.
 *
 * @param dest Pointer to buffer to store output hex string characters.
 * @param v    Value to convert.
 */
static void IntToGdbHex(u8* dest, u32 v) {
    for (int i = 0; i < 8; i += 2) {
        dest[i + 1] = NibbleToHex(static_cast<u8>(v >> (4 * i)));
        dest[i] = NibbleToHex(static_cast<u8>(v >> (4 * (i + 1))));
    }
}

/**
 * Convert a u64 into a gdb-formatted hex string.
 *
 * @param dest Pointer to buffer to store output hex string characters.
 * @param v    Value to convert.
 */
static void LongToGdbHex(u8* dest, u64 v) {
    for (int i = 0; i < 16; i += 2) {
        dest[i + 1] = NibbleToHex(static_cast<u8>(v >> (4 * i)));
        dest[i] = NibbleToHex(static_cast<u8>(v >> (4 * (i + 1))));
    }
}

/**
 * Convert a gdb-formatted hex string into a u32.
 *
 * @param src Pointer to hex string.
 */
static u32 GdbHexToInt(const u8* src) {
    u32 output = 0;

    for (int i = 0; i < 8; i += 2) {
        output = (output << 4) | HexCharToValue(src[7 - i - 1]);
        output = (output << 4) | HexCharToValue(src[7 - i]);
    }

    return output;
}

/**
 * Convert a gdb-formatted hex string into a u64.
 *
 * @param src Pointer to hex string.
 */
static u64 GdbHexToLong(const u8* src) {
    u64 output = 0;

    for (int i = 0; i < 16; i += 2) {
        output = (output << 4) | HexCharToValue(src[15 - i - 1]);
        output = (output << 4) | HexCharToValue(src[15 - i]);
    }

    return output;
}

/// Read a byte from the gdb client.
static u8 ReadByte() {
    u8 c;
    std::size_t received_size = recv(gdbserver_socket, reinterpret_cast<char*>(&c), 1, MSG_WAITALL);
    if (received_size != 1) {
        LOG_ERROR(Debug_GDBStub, "recv failed: {}", received_size);
        Shutdown();
    }

    return c;
}

/// Calculate the checksum of the current command buffer.
static u8 CalculateChecksum(const u8* buffer, std::size_t length) {
    return static_cast<u8>(std::accumulate(buffer, buffer + length, 0, std::plus<u8>()));
}

/**
 * Get the map of breakpoints for a given breakpoint type.
 *
 * @param type Type of breakpoint map.
 */
static BreakpointMap& GetBreakpointMap(BreakpointType type) {
    switch (type) {
    case BreakpointType::Execute:
        return breakpoints_execute;
    case BreakpointType::Read:
        return breakpoints_read;
    case BreakpointType::Write:
        return breakpoints_write;
    default:
        return breakpoints_read;
    }
}

/**
 * Remove the breakpoint from the given address of the specified type.
 *
 * @param type Type of breakpoint.
 * @param addr Address of breakpoint.
 */
static void RemoveBreakpoint(BreakpointType type, VAddr addr) {
    BreakpointMap& p = GetBreakpointMap(type);

    const auto bp = p.find(addr);
    if (bp == p.end()) {
        return;
    }

    LOG_DEBUG(Debug_GDBStub, "gdb: removed a breakpoint: {:016X} bytes at {:016X} of type {}",
              bp->second.len, bp->second.addr, static_cast<int>(type));
    Memory::WriteBlock(bp->second.addr, bp->second.inst.data(), bp->second.inst.size());
    Core::System::GetInstance().InvalidateCpuInstructionCaches();
    p.erase(addr);
}

BreakpointAddress GetNextBreakpointFromAddress(VAddr addr, BreakpointType type) {
    const BreakpointMap& p = GetBreakpointMap(type);
    const auto next_breakpoint = p.lower_bound(addr);
    BreakpointAddress breakpoint;

    if (next_breakpoint != p.end()) {
        breakpoint.address = next_breakpoint->first;
        breakpoint.type = type;
    } else {
        breakpoint.address = 0;
        breakpoint.type = BreakpointType::None;
    }

    return breakpoint;
}

bool CheckBreakpoint(VAddr addr, BreakpointType type) {
    if (!IsConnected()) {
        return false;
    }

    const BreakpointMap& p = GetBreakpointMap(type);
    const auto bp = p.find(addr);

    if (bp == p.end()) {
        return false;
    }

    u64 len = bp->second.len;

    // IDA Pro defaults to 4-byte breakpoints for all non-hardware breakpoints
    // no matter if it's a 4-byte or 2-byte instruction. When you execute a
    // Thumb instruction with a 4-byte breakpoint set, it will set a breakpoint on
    // two instructions instead of the single instruction you placed the breakpoint
    // on. So, as a way to make sure that execution breakpoints are only breaking
    // on the instruction that was specified, set the length of an execution
    // breakpoint to 1. This should be fine since the CPU should never begin executing
    // an instruction anywhere except the beginning of the instruction.
    if (type == BreakpointType::Execute) {
        len = 1;
    }

    if (bp->second.active && (addr >= bp->second.addr && addr < bp->second.addr + len)) {
        LOG_DEBUG(Debug_GDBStub,
                  "Found breakpoint type {} @ {:016X}, range: {:016X}"
                  " - {:016X} ({:X} bytes)",
                  static_cast<int>(type), addr, bp->second.addr, bp->second.addr + len, len);
        return true;
    }

    return false;
}

/**
 * Send packet to gdb client.
 *
 * @param packet Packet to be sent to client.
 */
static void SendPacket(const char packet) {
    std::size_t sent_size = send(gdbserver_socket, &packet, 1, 0);
    if (sent_size != 1) {
        LOG_ERROR(Debug_GDBStub, "send failed");
    }
}

/**
 * Send reply to gdb client.
 *
 * @param reply Reply to be sent to client.
 */
static void SendReply(const char* reply) {
    if (!IsConnected()) {
        return;
    }

    LOG_DEBUG(Debug_GDBStub, "Reply: {}", reply);

    memset(command_buffer, 0, sizeof(command_buffer));

    command_length = static_cast<u32>(strlen(reply));
    if (command_length + 4 > sizeof(command_buffer)) {
        LOG_ERROR(Debug_GDBStub, "command_buffer overflow in SendReply");
        return;
    }

    memcpy(command_buffer + 1, reply, command_length);

    u8 checksum = CalculateChecksum(command_buffer, command_length + 1);
    command_buffer[0] = GDB_STUB_START;
    command_buffer[command_length + 1] = GDB_STUB_END;
    command_buffer[command_length + 2] = NibbleToHex(checksum >> 4);
    command_buffer[command_length + 3] = NibbleToHex(checksum);

    u8* ptr = command_buffer;
    u32 left = command_length + 4;
    while (left > 0) {
        int sent_size = send(gdbserver_socket, reinterpret_cast<char*>(ptr), left, 0);
        if (sent_size < 0) {
            LOG_ERROR(Debug_GDBStub, "gdb: send failed");
            return Shutdown();
        }

        left -= sent_size;
        ptr += sent_size;
    }
}

/// Handle query command from gdb client.
static void HandleQuery() {
    LOG_DEBUG(Debug_GDBStub, "gdb: query '{}'", command_buffer + 1);

    const char* query = reinterpret_cast<const char*>(command_buffer + 1);

    if (strcmp(query, "TStatus") == 0) {
        SendReply("T0");
    } else if (strncmp(query, "Supported", strlen("Supported")) == 0) {
        // PacketSize needs to be large enough for target xml
        std::string buffer = "PacketSize=2000;qXfer:features:read+;qXfer:threads:read+";
        if (!modules.empty()) {
            buffer += ";qXfer:libraries:read+";
        }
        SendReply(buffer.c_str());
    } else if (strncmp(query, "Xfer:features:read:target.xml:",
                       strlen("Xfer:features:read:target.xml:")) == 0) {
        SendReply(target_xml);
    } else if (strncmp(query, "Offsets", strlen("Offsets")) == 0) {
        std::string buffer = fmt::format("TextSeg={:0x}", Memory::PROCESS_IMAGE_VADDR);
        SendReply(buffer.c_str());
    } else if (strncmp(query, "fThreadInfo", strlen("fThreadInfo")) == 0) {
        std::string val = "m";
        for (u32 core = 0; core < Core::NUM_CPU_CORES; core++) {
            const auto& threads = Core::System::GetInstance().Scheduler(core)->GetThreadList();
            for (const auto& thread : threads) {
                val += fmt::format("{:x}", thread->GetThreadId());
                val += ",";
            }
        }
        val.pop_back();
        SendReply(val.c_str());
    } else if (strncmp(query, "sThreadInfo", strlen("sThreadInfo")) == 0) {
        SendReply("l");
    } else if (strncmp(query, "Xfer:threads:read", strlen("Xfer:threads:read")) == 0) {
        std::string buffer;
        buffer += "l<?xml version=\"1.0\"?>";
        buffer += "<threads>";
        for (u32 core = 0; core < Core::NUM_CPU_CORES; core++) {
            const auto& threads = Core::System::GetInstance().Scheduler(core)->GetThreadList();
            for (const auto& thread : threads) {
                buffer +=
                    fmt::format(R"*(<thread id="{:x}" core="{:d}" name="Thread {:x}"></thread>)*",
                                thread->GetThreadId(), core, thread->GetThreadId());
            }
        }
        buffer += "</threads>";
        SendReply(buffer.c_str());
    } else if (strncmp(query, "Xfer:libraries:read", strlen("Xfer:libraries:read")) == 0) {
        std::string buffer;
        buffer += "l<?xml version=\"1.0\"?>";
        buffer += "<library-list>";
        for (const auto& module : modules) {
            buffer +=
                fmt::format(R"*("<library name = "{}"><segment address = "0x{:x}"/></library>)*",
                            module.name, module.beg);
        }
        buffer += "</library-list>";
        SendReply(buffer.c_str());
    } else {
        SendReply("");
    }
}

/// Handle set thread command from gdb client.
static void HandleSetThread() {
    int thread_id = -1;
    if (command_buffer[2] != '-') {
        thread_id = static_cast<int>(HexToInt(command_buffer + 2, command_length - 2));
    }
    if (thread_id >= 1) {
        current_thread = FindThreadById(thread_id);
    }
    if (!current_thread) {
        thread_id = 1;
        current_thread = FindThreadById(thread_id);
    }
    if (current_thread) {
        SendReply("OK");
        return;
    }
    SendReply("E01");
}

/// Handle thread alive command from gdb client.
static void HandleThreadAlive() {
    int thread_id = static_cast<int>(HexToInt(command_buffer + 1, command_length - 1));
    if (thread_id == 0) {
        thread_id = 1;
    }
    if (FindThreadById(thread_id)) {
        SendReply("OK");
        return;
    }
    SendReply("E01");
}

/**
 * Send signal packet to client.
 *
 * @param signal Signal to be sent to client.
 */
static void SendSignal(Kernel::Thread* thread, u32 signal, bool full = true) {
    if (gdbserver_socket == -1) {
        return;
    }

    latest_signal = signal;

    if (!thread) {
        full = false;
    }

    std::string buffer;
    if (full) {
        buffer = fmt::format("T{:02x}{:02x}:{:016x};{:02x}:{:016x};{:02x}:{:016x}", latest_signal,
                             PC_REGISTER, Common::swap64(RegRead(PC_REGISTER, thread)), SP_REGISTER,
                             Common::swap64(RegRead(SP_REGISTER, thread)), LR_REGISTER,
                             Common::swap64(RegRead(LR_REGISTER, thread)));
    } else {
        buffer = fmt::format("T{:02x}", latest_signal);
    }

    if (thread) {
        buffer += fmt::format(";thread:{:x};", thread->GetThreadId());
    }

    SendReply(buffer.c_str());
}

/// Read command from gdb client.
static void ReadCommand() {
    command_length = 0;
    memset(command_buffer, 0, sizeof(command_buffer));

    u8 c = ReadByte();
    if (c == '+') {
        // ignore ack
        return;
    } else if (c == 0x03) {
        LOG_INFO(Debug_GDBStub, "gdb: found break command");
        halt_loop = true;
        SendSignal(current_thread, SIGTRAP);
        return;
    } else if (c != GDB_STUB_START) {
        LOG_DEBUG(Debug_GDBStub, "gdb: read invalid byte {:02X}", c);
        return;
    }

    while ((c = ReadByte()) != GDB_STUB_END) {
        if (command_length >= sizeof(command_buffer)) {
            LOG_ERROR(Debug_GDBStub, "gdb: command_buffer overflow");
            SendPacket(GDB_STUB_NACK);
            return;
        }
        command_buffer[command_length++] = c;
    }

    u8 checksum_received = HexCharToValue(ReadByte()) << 4;
    checksum_received |= HexCharToValue(ReadByte());

    u8 checksum_calculated = CalculateChecksum(command_buffer, command_length);

    if (checksum_received != checksum_calculated) {
        LOG_ERROR(Debug_GDBStub,
                  "gdb: invalid checksum: calculated {:02X} and read {:02X} for ${}# (length: {})",
                  checksum_calculated, checksum_received, command_buffer, command_length);

        command_length = 0;

        SendPacket(GDB_STUB_NACK);
        return;
    }

    SendPacket(GDB_STUB_ACK);
}

/// Check if there is data to be read from the gdb client.
static bool IsDataAvailable() {
    if (!IsConnected()) {
        return false;
    }

    fd_set fd_socket;

    FD_ZERO(&fd_socket);
    FD_SET(static_cast<u32>(gdbserver_socket), &fd_socket);

    struct timeval t;
    t.tv_sec = 0;
    t.tv_usec = 0;

    if (select(gdbserver_socket + 1, &fd_socket, nullptr, nullptr, &t) < 0) {
        LOG_ERROR(Debug_GDBStub, "select failed");
        return false;
    }

    return FD_ISSET(gdbserver_socket, &fd_socket) != 0;
}

/// Send requested register to gdb client.
static void ReadRegister() {
    static u8 reply[64];
    memset(reply, 0, sizeof(reply));

    u32 id = HexCharToValue(command_buffer[1]);
    if (command_buffer[2] != '\0') {
        id <<= 4;
        id |= HexCharToValue(command_buffer[2]);
    }

    if (id <= SP_REGISTER) {
        LongToGdbHex(reply, RegRead(id, current_thread));
    } else if (id == PC_REGISTER) {
        LongToGdbHex(reply, RegRead(id, current_thread));
    } else if (id == CPSR_REGISTER) {
        IntToGdbHex(reply, (u32)RegRead(id, current_thread));
    } else if (id >= UC_ARM64_REG_Q0 && id < FPSCR_REGISTER) {
        LongToGdbHex(reply, RegRead(id, current_thread));
    } else if (id == FPSCR_REGISTER) {
        LongToGdbHex(reply, RegRead(TODO_DUMMY_REG_998, current_thread));
    } else {
        LongToGdbHex(reply, RegRead(TODO_DUMMY_REG_997, current_thread));
    }

    SendReply(reinterpret_cast<char*>(reply));
}

/// Send all registers to the gdb client.
static void ReadRegisters() {
    static u8 buffer[GDB_BUFFER_SIZE - 4];
    memset(buffer, 0, sizeof(buffer));

    u8* bufptr = buffer;

    for (u32 reg = 0; reg <= SP_REGISTER; reg++) {
        LongToGdbHex(bufptr + reg * 16, RegRead(reg, current_thread));
    }

    bufptr += 32 * 16;

    LongToGdbHex(bufptr, RegRead(PC_REGISTER, current_thread));

    bufptr += 16;

    IntToGdbHex(bufptr, (u32)RegRead(CPSR_REGISTER, current_thread));

    bufptr += 8;

    for (u32 reg = UC_ARM64_REG_Q0; reg <= UC_ARM64_REG_Q0 + 31; reg++) {
        LongToGdbHex(bufptr + reg * 16, RegRead(reg, current_thread));
    }

    bufptr += 32 * 32;

    LongToGdbHex(bufptr, RegRead(TODO_DUMMY_REG_998, current_thread));

    bufptr += 8;

    SendReply(reinterpret_cast<char*>(buffer));
}

/// Modify data of register specified by gdb client.
static void WriteRegister() {
    const u8* buffer_ptr = command_buffer + 3;

    u32 id = HexCharToValue(command_buffer[1]);
    if (command_buffer[2] != '=') {
        ++buffer_ptr;
        id <<= 4;
        id |= HexCharToValue(command_buffer[2]);
    }

    if (id <= SP_REGISTER) {
        RegWrite(id, GdbHexToLong(buffer_ptr), current_thread);
    } else if (id == PC_REGISTER) {
        RegWrite(id, GdbHexToLong(buffer_ptr), current_thread);
    } else if (id == CPSR_REGISTER) {
        RegWrite(id, GdbHexToInt(buffer_ptr), current_thread);
    } else if (id >= UC_ARM64_REG_Q0 && id < FPSCR_REGISTER) {
        RegWrite(id, GdbHexToLong(buffer_ptr), current_thread);
    } else if (id == FPSCR_REGISTER) {
        RegWrite(TODO_DUMMY_REG_998, GdbHexToLong(buffer_ptr), current_thread);
    } else {
        RegWrite(TODO_DUMMY_REG_997, GdbHexToLong(buffer_ptr), current_thread);
    }

    // Update Unicorn context skipping scheduler, no running threads at this point
    Core::System::GetInstance().ArmInterface(current_core).LoadContext(current_thread->context);

    SendReply("OK");
}

/// Modify all registers with data received from the client.
static void WriteRegisters() {
    const u8* buffer_ptr = command_buffer + 1;

    if (command_buffer[0] != 'G')
        return SendReply("E01");

    for (u32 i = 0, reg = 0; reg <= FPSCR_REGISTER; i++, reg++) {
        if (reg <= SP_REGISTER) {
            RegWrite(reg, GdbHexToLong(buffer_ptr + i * 16), current_thread);
        } else if (reg == PC_REGISTER) {
            RegWrite(PC_REGISTER, GdbHexToLong(buffer_ptr + i * 16), current_thread);
        } else if (reg == CPSR_REGISTER) {
            RegWrite(CPSR_REGISTER, GdbHexToInt(buffer_ptr + i * 16), current_thread);
        } else if (reg >= UC_ARM64_REG_Q0 && reg < FPSCR_REGISTER) {
            RegWrite(reg, GdbHexToLong(buffer_ptr + i * 16), current_thread);
        } else if (reg == FPSCR_REGISTER) {
            RegWrite(TODO_DUMMY_REG_998, GdbHexToLong(buffer_ptr + i * 16), current_thread);
        } else {
            UNIMPLEMENTED();
        }
    }

    // Update Unicorn context skipping scheduler, no running threads at this point
    Core::System::GetInstance().ArmInterface(current_core).LoadContext(current_thread->context);

    SendReply("OK");
}

/// Read location in memory specified by gdb client.
static void ReadMemory() {
    static u8 reply[GDB_BUFFER_SIZE - 4];

    auto start_offset = command_buffer + 1;
    auto addr_pos = std::find(start_offset, command_buffer + command_length, ',');
    VAddr addr = HexToLong(start_offset, static_cast<u64>(addr_pos - start_offset));

    start_offset = addr_pos + 1;
    u64 len =
        HexToLong(start_offset, static_cast<u64>((command_buffer + command_length) - start_offset));

    LOG_DEBUG(Debug_GDBStub, "gdb: addr: {:016X} len: {:016X}", addr, len);

    if (len * 2 > sizeof(reply)) {
        SendReply("E01");
    }

    if (addr < Memory::PROCESS_IMAGE_VADDR || addr >= Memory::MAP_REGION_VADDR_END) {
        return SendReply("E00");
    }

    if (!Memory::IsValidVirtualAddress(addr)) {
        return SendReply("E00");
    }

    std::vector<u8> data(len);
    Memory::ReadBlock(addr, data.data(), len);

    MemToGdbHex(reply, data.data(), len);
    reply[len * 2] = '\0';
    SendReply(reinterpret_cast<char*>(reply));
}

/// Modify location in memory with data received from the gdb client.
static void WriteMemory() {
    auto start_offset = command_buffer + 1;
    auto addr_pos = std::find(start_offset, command_buffer + command_length, ',');
    VAddr addr = HexToLong(start_offset, static_cast<u64>(addr_pos - start_offset));

    start_offset = addr_pos + 1;
    auto len_pos = std::find(start_offset, command_buffer + command_length, ':');
    u64 len = HexToLong(start_offset, static_cast<u64>(len_pos - start_offset));

    if (!Memory::IsValidVirtualAddress(addr)) {
        return SendReply("E00");
    }

    std::vector<u8> data(len);

    GdbHexToMem(data.data(), len_pos + 1, len);
    Memory::WriteBlock(addr, data.data(), len);
    Core::System::GetInstance().InvalidateCpuInstructionCaches();
    SendReply("OK");
}

void Break(bool is_memory_break) {
    send_trap = true;

    memory_break = is_memory_break;
}

/// Tell the CPU that it should perform a single step.
static void Step() {
    if (command_length > 1) {
        RegWrite(PC_REGISTER, GdbHexToLong(command_buffer + 1), current_thread);
        // Update Unicorn context skipping scheduler, no running threads at this point
        Core::System::GetInstance().ArmInterface(current_core).LoadContext(current_thread->context);
    }
    step_loop = true;
    halt_loop = true;
    send_trap = true;
    Core::System::GetInstance().InvalidateCpuInstructionCaches();
}

/// Tell the CPU if we hit a memory breakpoint.
bool IsMemoryBreak() {
    if (IsConnected()) {
        return false;
    }

    return memory_break;
}

/// Tell the CPU to continue executing.
static void Continue() {
    memory_break = false;
    step_loop = false;
    halt_loop = false;
    Core::System::GetInstance().InvalidateCpuInstructionCaches();
}

/**
 * Commit breakpoint to list of breakpoints.
 *
 * @param type Type of breakpoint.
 * @param addr Address of breakpoint.
 * @param len Length of breakpoint.
 */
static bool CommitBreakpoint(BreakpointType type, VAddr addr, u64 len) {
    BreakpointMap& p = GetBreakpointMap(type);

    Breakpoint breakpoint;
    breakpoint.active = true;
    breakpoint.addr = addr;
    breakpoint.len = len;
    Memory::ReadBlock(addr, breakpoint.inst.data(), breakpoint.inst.size());
    static constexpr std::array<u8, 4> btrap{{0xd4, 0x20, 0x7d, 0x0}};
    Memory::WriteBlock(addr, btrap.data(), btrap.size());
    Core::System::GetInstance().InvalidateCpuInstructionCaches();
    p.insert({addr, breakpoint});

    LOG_DEBUG(Debug_GDBStub, "gdb: added {} breakpoint: {:016X} bytes at {:016X}",
              static_cast<int>(type), breakpoint.len, breakpoint.addr);

    return true;
}

/// Handle add breakpoint command from gdb client.
static void AddBreakpoint() {
    BreakpointType type;

    u8 type_id = HexCharToValue(command_buffer[1]);
    switch (type_id) {
    case 0:
    case 1:
        type = BreakpointType::Execute;
        break;
    case 2:
        type = BreakpointType::Write;
        break;
    case 3:
        type = BreakpointType::Read;
        break;
    case 4:
        type = BreakpointType::Access;
        break;
    default:
        return SendReply("E01");
    }

    auto start_offset = command_buffer + 3;
    auto addr_pos = std::find(start_offset, command_buffer + command_length, ',');
    VAddr addr = HexToLong(start_offset, static_cast<u64>(addr_pos - start_offset));

    start_offset = addr_pos + 1;
    u64 len =
        HexToLong(start_offset, static_cast<u64>((command_buffer + command_length) - start_offset));

    if (type == BreakpointType::Access) {
        // Access is made up of Read and Write types, so add both breakpoints
        type = BreakpointType::Read;

        if (!CommitBreakpoint(type, addr, len)) {
            return SendReply("E02");
        }

        type = BreakpointType::Write;
    }

    if (!CommitBreakpoint(type, addr, len)) {
        return SendReply("E02");
    }

    SendReply("OK");
}

/// Handle remove breakpoint command from gdb client.
static void RemoveBreakpoint() {
    BreakpointType type;

    u8 type_id = HexCharToValue(command_buffer[1]);
    switch (type_id) {
    case 0:
    case 1:
        type = BreakpointType::Execute;
        break;
    case 2:
        type = BreakpointType::Write;
        break;
    case 3:
        type = BreakpointType::Read;
        break;
    case 4:
        type = BreakpointType::Access;
        break;
    default:
        return SendReply("E01");
    }

    auto start_offset = command_buffer + 3;
    auto addr_pos = std::find(start_offset, command_buffer + command_length, ',');
    VAddr addr = HexToLong(start_offset, static_cast<u64>(addr_pos - start_offset));

    if (type == BreakpointType::Access) {
        // Access is made up of Read and Write types, so add both breakpoints
        type = BreakpointType::Read;
        RemoveBreakpoint(type, addr);

        type = BreakpointType::Write;
    }

    RemoveBreakpoint(type, addr);
    SendReply("OK");
}

void HandlePacket() {
    if (!IsConnected()) {
        return;
    }

    if (!IsDataAvailable()) {
        return;
    }

    ReadCommand();
    if (command_length == 0) {
        return;
    }

    LOG_DEBUG(Debug_GDBStub, "Packet: {}", command_buffer);

    switch (command_buffer[0]) {
    case 'q':
        HandleQuery();
        break;
    case 'H':
        HandleSetThread();
        break;
    case '?':
        SendSignal(current_thread, latest_signal);
        break;
    case 'k':
        Shutdown();
        LOG_INFO(Debug_GDBStub, "killed by gdb");
        return;
    case 'g':
        ReadRegisters();
        break;
    case 'G':
        WriteRegisters();
        break;
    case 'p':
        ReadRegister();
        break;
    case 'P':
        WriteRegister();
        break;
    case 'm':
        ReadMemory();
        break;
    case 'M':
        WriteMemory();
        break;
    case 's':
        Step();
        return;
    case 'C':
    case 'c':
        Continue();
        return;
    case 'z':
        RemoveBreakpoint();
        break;
    case 'Z':
        AddBreakpoint();
        break;
    case 'T':
        HandleThreadAlive();
        break;
    default:
        SendReply("");
        break;
    }
}

void SetServerPort(u16 port) {
    gdbstub_port = port;
}

void ToggleServer(bool status) {
    if (status) {
        server_enabled = status;

        // Start server
        if (!IsConnected() && Core::System::GetInstance().IsPoweredOn()) {
            Init();
        }
    } else {
        // Stop server
        if (IsConnected()) {
            Shutdown();
        }

        server_enabled = status;
    }
}

static void Init(u16 port) {
    if (!server_enabled) {
        // Set the halt loop to false in case the user enabled the gdbstub mid-execution.
        // This way the CPU can still execute normally.
        halt_loop = false;
        step_loop = false;
        return;
    }

    // Setup initial gdbstub status
    halt_loop = true;
    step_loop = false;

    breakpoints_execute.clear();
    breakpoints_read.clear();
    breakpoints_write.clear();

    modules.clear();

    // Start gdb server
    LOG_INFO(Debug_GDBStub, "Starting GDB server on port {}...", port);

    sockaddr_in saddr_server = {};
    saddr_server.sin_family = AF_INET;
    saddr_server.sin_port = htons(port);
    saddr_server.sin_addr.s_addr = INADDR_ANY;

#ifdef _WIN32
    WSAStartup(MAKEWORD(2, 2), &InitData);
#endif

    int tmpsock = static_cast<int>(socket(PF_INET, SOCK_STREAM, 0));
    if (tmpsock == -1) {
        LOG_ERROR(Debug_GDBStub, "Failed to create gdb socket");
    }

    // Set socket to SO_REUSEADDR so it can always bind on the same port
    int reuse_enabled = 1;
    if (setsockopt(tmpsock, SOL_SOCKET, SO_REUSEADDR, (const char*)&reuse_enabled,
                   sizeof(reuse_enabled)) < 0) {
        LOG_ERROR(Debug_GDBStub, "Failed to set gdb socket option");
    }

    const sockaddr* server_addr = reinterpret_cast<const sockaddr*>(&saddr_server);
    socklen_t server_addrlen = sizeof(saddr_server);
    if (bind(tmpsock, server_addr, server_addrlen) < 0) {
        LOG_ERROR(Debug_GDBStub, "Failed to bind gdb socket");
    }

    if (listen(tmpsock, 1) < 0) {
        LOG_ERROR(Debug_GDBStub, "Failed to listen to gdb socket");
    }

    // Wait for gdb to connect
    LOG_INFO(Debug_GDBStub, "Waiting for gdb to connect...");
    sockaddr_in saddr_client;
    sockaddr* client_addr = reinterpret_cast<sockaddr*>(&saddr_client);
    socklen_t client_addrlen = sizeof(saddr_client);
    gdbserver_socket = static_cast<int>(accept(tmpsock, client_addr, &client_addrlen));
    if (gdbserver_socket < 0) {
        // In the case that we couldn't start the server for whatever reason, just start CPU
        // execution like normal.
        halt_loop = false;
        step_loop = false;

        LOG_ERROR(Debug_GDBStub, "Failed to accept gdb client");
    } else {
        LOG_INFO(Debug_GDBStub, "Client connected.");
        saddr_client.sin_addr.s_addr = ntohl(saddr_client.sin_addr.s_addr);
    }

    // Clean up temporary socket if it's still alive at this point.
    if (tmpsock != -1) {
        shutdown(tmpsock, SHUT_RDWR);
    }
}

void Init() {
    Init(gdbstub_port);
}

void Shutdown() {
    if (!server_enabled) {
        return;
    }

    LOG_INFO(Debug_GDBStub, "Stopping GDB ...");
    if (gdbserver_socket != -1) {
        shutdown(gdbserver_socket, SHUT_RDWR);
        gdbserver_socket = -1;
    }

#ifdef _WIN32
    WSACleanup();
#endif

    LOG_INFO(Debug_GDBStub, "GDB stopped.");
}

bool IsServerEnabled() {
    return server_enabled;
}

bool IsConnected() {
    return IsServerEnabled() && gdbserver_socket != -1;
}

bool GetCpuHaltFlag() {
    return halt_loop;
}

bool GetCpuStepFlag() {
    return step_loop;
}

void SetCpuStepFlag(bool is_step) {
    step_loop = is_step;
}

void SendTrap(Kernel::Thread* thread, int trap) {
    if (send_trap) {
        if (!halt_loop || current_thread == thread) {
            current_thread = thread;
            SendSignal(thread, trap);
        }
        halt_loop = true;
        send_trap = false;
    }
}
}; // namespace GDBStub