aboutsummaryrefslogtreecommitdiffstats
path: root/source/Plugins/Process/Utility/StopInfoMachException.cpp
blob: 6d03bd534f37f3485852f0a1b77e62dc95fab72c (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
//===-- StopInfoMachException.cpp -------------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#include "StopInfoMachException.h"


#if defined(__APPLE__)
// Needed for the EXC_RESOURCE interpretation macros
#include <kern/exc_resource.h>
#endif

#include "lldb/Breakpoint/Watchpoint.h"
#include "lldb/Symbol/Symbol.h"
#include "lldb/Target/DynamicLoader.h"
#include "lldb/Target/ExecutionContext.h"
#include "lldb/Target/Process.h"
#include "lldb/Target/RegisterContext.h"
#include "lldb/Target/Target.h"
#include "lldb/Target/Thread.h"
#include "lldb/Target/ThreadPlan.h"
#include "lldb/Target/UnixSignals.h"
#include "lldb/Utility/StreamString.h"

using namespace lldb;
using namespace lldb_private;

const char *StopInfoMachException::GetDescription() {
  if (!m_description.empty())
    return m_description.c_str();
  if (GetValue() == eStopReasonInvalid)
    return "invalid stop reason!";

  ExecutionContext exe_ctx(m_thread_wp.lock());
  Target *target = exe_ctx.GetTargetPtr();
  const llvm::Triple::ArchType cpu =
      target ? target->GetArchitecture().GetMachine()
             : llvm::Triple::UnknownArch;

  const char *exc_desc = nullptr;
  const char *code_label = "code";
  const char *code_desc = nullptr;
  const char *subcode_label = "subcode";
  const char *subcode_desc = nullptr;

#if defined(__APPLE__)
  char code_desc_buf[32];
  char subcode_desc_buf[32];
#endif

  switch (m_value) {
  case 1: // EXC_BAD_ACCESS
    exc_desc = "EXC_BAD_ACCESS";
    subcode_label = "address";
    switch (cpu) {
    case llvm::Triple::x86:
    case llvm::Triple::x86_64:
      switch (m_exc_code) {
      case 0xd:
        code_desc = "EXC_I386_GPFLT";
        m_exc_data_count = 1;
        break;
      }
      break;
    case llvm::Triple::arm:
    case llvm::Triple::thumb:
      switch (m_exc_code) {
      case 0x101:
        code_desc = "EXC_ARM_DA_ALIGN";
        break;
      case 0x102:
        code_desc = "EXC_ARM_DA_DEBUG";
        break;
      }
      break;

    default:
      break;
    }
    break;

  case 2: // EXC_BAD_INSTRUCTION
    exc_desc = "EXC_BAD_INSTRUCTION";
    switch (cpu) {
    case llvm::Triple::x86:
    case llvm::Triple::x86_64:
      if (m_exc_code == 1)
        code_desc = "EXC_I386_INVOP";
      break;

    case llvm::Triple::arm:
    case llvm::Triple::thumb:
      if (m_exc_code == 1)
        code_desc = "EXC_ARM_UNDEFINED";
      break;

    default:
      break;
    }
    break;

  case 3: // EXC_ARITHMETIC
    exc_desc = "EXC_ARITHMETIC";
    switch (cpu) {
    case llvm::Triple::x86:
    case llvm::Triple::x86_64:
      switch (m_exc_code) {
      case 1:
        code_desc = "EXC_I386_DIV";
        break;
      case 2:
        code_desc = "EXC_I386_INTO";
        break;
      case 3:
        code_desc = "EXC_I386_NOEXT";
        break;
      case 4:
        code_desc = "EXC_I386_EXTOVR";
        break;
      case 5:
        code_desc = "EXC_I386_EXTERR";
        break;
      case 6:
        code_desc = "EXC_I386_EMERR";
        break;
      case 7:
        code_desc = "EXC_I386_BOUND";
        break;
      case 8:
        code_desc = "EXC_I386_SSEEXTERR";
        break;
      }
      break;

    default:
      break;
    }
    break;

  case 4: // EXC_EMULATION
    exc_desc = "EXC_EMULATION";
    break;

  case 5: // EXC_SOFTWARE
    exc_desc = "EXC_SOFTWARE";
    if (m_exc_code == 0x10003) {
      subcode_desc = "EXC_SOFT_SIGNAL";
      subcode_label = "signo";
    }
    break;

  case 6: // EXC_BREAKPOINT
  {
    exc_desc = "EXC_BREAKPOINT";
    switch (cpu) {
    case llvm::Triple::x86:
    case llvm::Triple::x86_64:
      switch (m_exc_code) {
      case 1:
        code_desc = "EXC_I386_SGL";
        break;
      case 2:
        code_desc = "EXC_I386_BPT";
        break;
      }
      break;

    case llvm::Triple::arm:
    case llvm::Triple::thumb:
      switch (m_exc_code) {
      case 0x101:
        code_desc = "EXC_ARM_DA_ALIGN";
        break;
      case 0x102:
        code_desc = "EXC_ARM_DA_DEBUG";
        break;
      case 1:
        code_desc = "EXC_ARM_BREAKPOINT";
        break;
      // FIXME temporary workaround, exc_code 0 does not really mean
      // EXC_ARM_BREAKPOINT
      case 0:
        code_desc = "EXC_ARM_BREAKPOINT";
        break;
      }
      break;

    default:
      break;
    }
  } break;

  case 7:
    exc_desc = "EXC_SYSCALL";
    break;

  case 8:
    exc_desc = "EXC_MACH_SYSCALL";
    break;

  case 9:
    exc_desc = "EXC_RPC_ALERT";
    break;

  case 10:
    exc_desc = "EXC_CRASH";
    break;
  case 11:
    exc_desc = "EXC_RESOURCE";
#if defined(__APPLE__)
    {
      int resource_type = EXC_RESOURCE_DECODE_RESOURCE_TYPE(m_exc_code);

      code_label = "limit";
      code_desc = code_desc_buf;
      subcode_label = "observed";
      subcode_desc = subcode_desc_buf;

      switch (resource_type) {
      case RESOURCE_TYPE_CPU:
        exc_desc = "EXC_RESOURCE RESOURCE_TYPE_CPU";
        snprintf(code_desc_buf, sizeof(code_desc_buf), "%d%%",
                 (int)EXC_RESOURCE_CPUMONITOR_DECODE_PERCENTAGE(m_exc_code));
        snprintf(subcode_desc_buf, sizeof(subcode_desc_buf), "%d%%",
                 (int)EXC_RESOURCE_CPUMONITOR_DECODE_PERCENTAGE_OBSERVED(
                     m_exc_subcode));
        break;
      case RESOURCE_TYPE_WAKEUPS:
        exc_desc = "EXC_RESOURCE RESOURCE_TYPE_WAKEUPS";
        snprintf(
            code_desc_buf, sizeof(code_desc_buf), "%d w/s",
            (int)EXC_RESOURCE_CPUMONITOR_DECODE_WAKEUPS_PERMITTED(m_exc_code));
        snprintf(subcode_desc_buf, sizeof(subcode_desc_buf), "%d w/s",
                 (int)EXC_RESOURCE_CPUMONITOR_DECODE_WAKEUPS_OBSERVED(
                     m_exc_subcode));
        break;
      case RESOURCE_TYPE_MEMORY:
        exc_desc = "EXC_RESOURCE RESOURCE_TYPE_MEMORY";
        snprintf(code_desc_buf, sizeof(code_desc_buf), "%d MB",
                 (int)EXC_RESOURCE_HWM_DECODE_LIMIT(m_exc_code));
        subcode_desc = nullptr;
        subcode_label = "unused";
        break;
#if defined(RESOURCE_TYPE_IO)
      // RESOURCE_TYPE_IO is introduced in macOS SDK 10.12.
      case RESOURCE_TYPE_IO:
        exc_desc = "EXC_RESOURCE RESOURCE_TYPE_IO";
        snprintf(code_desc_buf, sizeof(code_desc_buf), "%d MB",
                 (int)EXC_RESOURCE_IO_DECODE_LIMIT(m_exc_code));
        snprintf(subcode_desc_buf, sizeof(subcode_desc_buf), "%d MB",
                 (int)EXC_RESOURCE_IO_OBSERVED(m_exc_subcode));
        ;
        break;
#endif
      }
    }
#endif
    break;
  case 12:
    exc_desc = "EXC_GUARD";
    break;
  }

  StreamString strm;

  if (exc_desc)
    strm.PutCString(exc_desc);
  else
    strm.Printf("EXC_??? (%" PRIu64 ")", m_value);

  if (m_exc_data_count >= 1) {
    if (code_desc)
      strm.Printf(" (%s=%s", code_label, code_desc);
    else
      strm.Printf(" (%s=%" PRIu64, code_label, m_exc_code);
  }

  if (m_exc_data_count >= 2) {
    if (subcode_desc)
      strm.Printf(", %s=%s", subcode_label, subcode_desc);
    else
      strm.Printf(", %s=0x%" PRIx64, subcode_label, m_exc_subcode);
  }

  if (m_exc_data_count > 0)
    strm.PutChar(')');

  m_description = strm.GetString();
  return m_description.c_str();
}

StopInfoSP StopInfoMachException::CreateStopReasonWithMachException(
    Thread &thread, uint32_t exc_type, uint32_t exc_data_count,
    uint64_t exc_code, uint64_t exc_sub_code, uint64_t exc_sub_sub_code,
    bool pc_already_adjusted, bool adjust_pc_if_needed) {
  if (exc_type == 0)
    return StopInfoSP();

  uint32_t pc_decrement = 0;
  ExecutionContext exe_ctx(thread.shared_from_this());
  Target *target = exe_ctx.GetTargetPtr();
  const llvm::Triple::ArchType cpu =
      target ? target->GetArchitecture().GetMachine()
             : llvm::Triple::UnknownArch;

  switch (exc_type) {
  case 1: // EXC_BAD_ACCESS
  case 2: // EXC_BAD_INSTRUCTION
  case 3: // EXC_ARITHMETIC
  case 4: // EXC_EMULATION
    break;

  case 5:                    // EXC_SOFTWARE
    if (exc_code == 0x10003) // EXC_SOFT_SIGNAL
    {
      if (exc_sub_code == 5) {
        // On MacOSX, a SIGTRAP can signify that a process has called exec,
        // so we should check with our dynamic loader to verify.
        ProcessSP process_sp(thread.GetProcess());
        if (process_sp) {
          DynamicLoader *dynamic_loader = process_sp->GetDynamicLoader();
          if (dynamic_loader && dynamic_loader->ProcessDidExec()) {
            // The program was re-exec'ed
            return StopInfo::CreateStopReasonWithExec(thread);
          }
        }
      }
      return StopInfo::CreateStopReasonWithSignal(thread, exc_sub_code);
    }
    break;

  case 6: // EXC_BREAKPOINT
  {
    bool is_actual_breakpoint = false;
    bool is_trace_if_actual_breakpoint_missing = false;
    switch (cpu) {
    case llvm::Triple::x86:
    case llvm::Triple::x86_64:
      if (exc_code == 1) // EXC_I386_SGL
      {
        if (!exc_sub_code) {
          // This looks like a plain trap.
          // Have to check if there is a breakpoint here as well.  When you
          // single-step onto a trap, the single step stops you not to trap.
          // Since we also do that check below, let's just use that logic.
          is_actual_breakpoint = true;
          is_trace_if_actual_breakpoint_missing = true;
        } else {

          // It's a watchpoint, then.
          // The exc_sub_code indicates the data break address.
          lldb::WatchpointSP wp_sp;
          if (target)
            wp_sp = target->GetWatchpointList().FindByAddress(
                (lldb::addr_t)exc_sub_code);
          if (wp_sp && wp_sp->IsEnabled()) {
            // Debugserver may piggyback the hardware index of the fired
            // watchpoint in the exception data. Set the hardware index if
            // that's the case.
            if (exc_data_count >= 3)
              wp_sp->SetHardwareIndex((uint32_t)exc_sub_sub_code);
            return StopInfo::CreateStopReasonWithWatchpointID(thread,
                                                              wp_sp->GetID());
          }
        }
      } else if (exc_code == 2 || // EXC_I386_BPT
                 exc_code == 3)   // EXC_I386_BPTFLT
      {
        // KDP returns EXC_I386_BPTFLT for trace breakpoints
        if (exc_code == 3)
          is_trace_if_actual_breakpoint_missing = true;

        is_actual_breakpoint = true;
        if (!pc_already_adjusted)
          pc_decrement = 1;
      }
      break;

    case llvm::Triple::arm:
    case llvm::Triple::thumb:
      if (exc_code == 0x102) // EXC_ARM_DA_DEBUG
      {
        // It's a watchpoint, then, if the exc_sub_code indicates a
        // known/enabled data break address from our watchpoint list.
        lldb::WatchpointSP wp_sp;
        if (target)
          wp_sp = target->GetWatchpointList().FindByAddress(
              (lldb::addr_t)exc_sub_code);
        if (wp_sp && wp_sp->IsEnabled()) {
          // Debugserver may piggyback the hardware index of the fired
          // watchpoint in the exception data. Set the hardware index if
          // that's the case.
          if (exc_data_count >= 3)
            wp_sp->SetHardwareIndex((uint32_t)exc_sub_sub_code);
          return StopInfo::CreateStopReasonWithWatchpointID(thread,
                                                            wp_sp->GetID());
        } else {
          is_actual_breakpoint = true;
          is_trace_if_actual_breakpoint_missing = true;
        }
      } else if (exc_code == 1) // EXC_ARM_BREAKPOINT
      {
        is_actual_breakpoint = true;
        is_trace_if_actual_breakpoint_missing = true;
      } else if (exc_code == 0) // FIXME not EXC_ARM_BREAKPOINT but a kernel
                                // is currently returning this so accept it
                                // as indicating a breakpoint until the
                                // kernel is fixed
      {
        is_actual_breakpoint = true;
        is_trace_if_actual_breakpoint_missing = true;
      }
      break;

    case llvm::Triple::aarch64_32:
    case llvm::Triple::aarch64: {
      if (exc_code == 1 && exc_sub_code == 0) // EXC_ARM_BREAKPOINT
      {
        // This is hit when we single instruction step aka MDSCR_EL1 SS bit 0
        // is set
        is_actual_breakpoint = false;
        is_trace_if_actual_breakpoint_missing = true;
      }
      if (exc_code == 0x102) // EXC_ARM_DA_DEBUG
      {
        // It's a watchpoint, then, if the exc_sub_code indicates a
        // known/enabled data break address from our watchpoint list.
        lldb::WatchpointSP wp_sp;
        if (target)
          wp_sp = target->GetWatchpointList().FindByAddress(
              (lldb::addr_t)exc_sub_code);
        if (wp_sp && wp_sp->IsEnabled()) {
          // Debugserver may piggyback the hardware index of the fired
          // watchpoint in the exception data. Set the hardware index if
          // that's the case.
          if (exc_data_count >= 3)
            wp_sp->SetHardwareIndex((uint32_t)exc_sub_sub_code);
          return StopInfo::CreateStopReasonWithWatchpointID(thread,
                                                            wp_sp->GetID());
        }
        // EXC_ARM_DA_DEBUG seems to be reused for EXC_BREAKPOINT as well as
        // EXC_BAD_ACCESS
        if (thread.GetTemporaryResumeState() == eStateStepping)
          return StopInfo::CreateStopReasonToTrace(thread);
      }
      // It looks like exc_sub_code has the 4 bytes of the instruction that
      // triggered the exception, i.e. our breakpoint opcode
      is_actual_breakpoint = exc_code == 1;
      break;
    }

    default:
      break;
    }

    if (is_actual_breakpoint) {
      RegisterContextSP reg_ctx_sp(thread.GetRegisterContext());
      addr_t pc = reg_ctx_sp->GetPC() - pc_decrement;

      ProcessSP process_sp(thread.CalculateProcess());

      lldb::BreakpointSiteSP bp_site_sp;
      if (process_sp)
        bp_site_sp = process_sp->GetBreakpointSiteList().FindByAddress(pc);
      if (bp_site_sp && bp_site_sp->IsEnabled()) {
        // Update the PC if we were asked to do so, but only do so if we find
        // a breakpoint that we know about cause this could be a trap
        // instruction in the code
        if (pc_decrement > 0 && adjust_pc_if_needed)
          reg_ctx_sp->SetPC(pc);

        // If the breakpoint is for this thread, then we'll report the hit,
        // but if it is for another thread, we can just report no reason.  We
        // don't need to worry about stepping over the breakpoint here, that
        // will be taken care of when the thread resumes and notices that
        // there's a breakpoint under the pc. If we have an operating system
        // plug-in, we might have set a thread specific breakpoint using the
        // operating system thread ID, so we can't make any assumptions about
        // the thread ID so we must always report the breakpoint regardless
        // of the thread.
        if (bp_site_sp->ValidForThisThread(&thread) ||
            thread.GetProcess()->GetOperatingSystem() != nullptr)
          return StopInfo::CreateStopReasonWithBreakpointSiteID(
              thread, bp_site_sp->GetID());
        else if (is_trace_if_actual_breakpoint_missing)
          return StopInfo::CreateStopReasonToTrace(thread);
        else
          return StopInfoSP();
      }

      // Don't call this a trace if we weren't single stepping this thread.
      if (is_trace_if_actual_breakpoint_missing &&
          thread.GetTemporaryResumeState() == eStateStepping) {
        return StopInfo::CreateStopReasonToTrace(thread);
      }
    }
  } break;

  case 7:  // EXC_SYSCALL
  case 8:  // EXC_MACH_SYSCALL
  case 9:  // EXC_RPC_ALERT
  case 10: // EXC_CRASH
    break;
  }

  return StopInfoSP(new StopInfoMachException(thread, exc_type, exc_data_count,
                                              exc_code, exc_sub_code));
}