aboutsummaryrefslogtreecommitdiff
path: root/src/client/mac/tests/exception_handler_test.cc
blob: 8325d44e173ee82466b2b2cd2922974527d64351 (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
// Copyright (c) 2010, Google Inc.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
//     * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

// exception_handler_test.cc: Unit tests for google_breakpad::ExceptionHandler

#include <pthread.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <unistd.h>

#include "breakpad_googletest_includes.h"
#include "client/mac/handler/exception_handler.h"
#include "common/mac/MachIPC.h"
#include "common/tests/auto_tempdir.h"
#include "google_breakpad/processor/minidump.h"

namespace google_breakpad {
// This acts as the log sink for INFO logging from the processor
// logging code. The logging output confuses XCode and makes it think
// there are unit test failures. testlogging.h handles the overriding.
std::ostringstream info_log;
}

namespace {
using std::string;
using google_breakpad::AutoTempDir;
using google_breakpad::ExceptionHandler;
using google_breakpad::MachPortSender;
using google_breakpad::MachReceiveMessage;
using google_breakpad::MachSendMessage;
using google_breakpad::Minidump;
using google_breakpad::MinidumpContext;
using google_breakpad::MinidumpException;
using google_breakpad::MinidumpMemoryList;
using google_breakpad::MinidumpMemoryRegion;
using google_breakpad::ReceivePort;
using testing::Test;

class ExceptionHandlerTest : public Test {
 public:
  void InProcessCrash(bool aborting);
  AutoTempDir tempDir;
  string lastDumpName;
};

static void Crasher() {
  int *a = (int*)0x42;

  fprintf(stdout, "Going to crash...\n");
  fprintf(stdout, "A = %d", *a);
}

static void AbortCrasher() {
  fprintf(stdout, "Going to crash...\n");
  abort();
}

static void SoonToCrash(void(*crasher)()) {
  crasher();
}

static bool MDCallback(const char *dump_dir, const char *file_name,
                       void *context, bool success) {
  string path(dump_dir);
  path.append("/");
  path.append(file_name);
  path.append(".dmp");

  int fd = *reinterpret_cast<int*>(context);
  (void)write(fd, path.c_str(), path.length() + 1);
  close(fd);
  exit(0);
  // not reached
  return true;
}

void ExceptionHandlerTest::InProcessCrash(bool aborting) {
  // Give the child process a pipe to report back on.
  int fds[2];
  ASSERT_EQ(0, pipe(fds));
  // Fork off a child process so it can crash.
  pid_t pid = fork();
  if (pid == 0) {
    // In the child process.
    close(fds[0]);
    ExceptionHandler eh(tempDir.path(), NULL, MDCallback, &fds[1], true, NULL);
    // crash
    SoonToCrash(aborting ? &AbortCrasher : &Crasher);
    // not reached
    exit(1);
  }
  // In the parent process.
  ASSERT_NE(-1, pid);
  // Wait for the background process to return the minidump file.
  close(fds[1]);
  char minidump_file[PATH_MAX];
  ssize_t nbytes = read(fds[0], minidump_file, sizeof(minidump_file));
  ASSERT_NE(0, nbytes);
  // Ensure that minidump file exists and is > 0 bytes.
  struct stat st;
  ASSERT_EQ(0, stat(minidump_file, &st));
  ASSERT_LT(0, st.st_size);

  // Child process should have exited with a zero status.
  int ret;
  ASSERT_EQ(pid, waitpid(pid, &ret, 0));
  EXPECT_NE(0, WIFEXITED(ret));
  EXPECT_EQ(0, WEXITSTATUS(ret));
}

TEST_F(ExceptionHandlerTest, InProcess) {
  InProcessCrash(false);
}

#if TARGET_OS_IPHONE
TEST_F(ExceptionHandlerTest, InProcessAbort) {
  InProcessCrash(true);
}
#endif

static bool DumpNameMDCallback(const char *dump_dir, const char *file_name,
                               void *context, bool success) {
  ExceptionHandlerTest *self = reinterpret_cast<ExceptionHandlerTest*>(context);
  if (dump_dir && file_name) {
    self->lastDumpName = dump_dir;
    self->lastDumpName += "/";
    self->lastDumpName += file_name;
    self->lastDumpName += ".dmp";
  }
  return true;
}

TEST_F(ExceptionHandlerTest, WriteMinidump) {
  ExceptionHandler eh(tempDir.path(), NULL, DumpNameMDCallback, this, true,
                      NULL);
  ASSERT_TRUE(eh.WriteMinidump());

  // Ensure that minidump file exists and is > 0 bytes.
  ASSERT_FALSE(lastDumpName.empty());
  struct stat st;
  ASSERT_EQ(0, stat(lastDumpName.c_str(), &st));
  ASSERT_LT(0, st.st_size);

  // The minidump should not contain an exception stream.
  Minidump minidump(lastDumpName);
  ASSERT_TRUE(minidump.Read());

  MinidumpException* exception = minidump.GetException();
  EXPECT_FALSE(exception);
}

TEST_F(ExceptionHandlerTest, WriteMinidumpWithException) {
  ExceptionHandler eh(tempDir.path(), NULL, DumpNameMDCallback, this, true,
                      NULL);
  ASSERT_TRUE(eh.WriteMinidump(true));

  // Ensure that minidump file exists and is > 0 bytes.
  ASSERT_FALSE(lastDumpName.empty());
  struct stat st;
  ASSERT_EQ(0, stat(lastDumpName.c_str(), &st));
  ASSERT_LT(0, st.st_size);

  // The minidump should contain an exception stream.
  Minidump minidump(lastDumpName);
  ASSERT_TRUE(minidump.Read());

  MinidumpException* exception = minidump.GetException();
  ASSERT_TRUE(exception);
  const MDRawExceptionStream* raw_exception = exception->exception();
  ASSERT_TRUE(raw_exception);

  EXPECT_EQ(MD_EXCEPTION_MAC_BREAKPOINT,
            raw_exception->exception_record.exception_code);
}

TEST_F(ExceptionHandlerTest, DumpChildProcess) {
  const int kTimeoutMs = 2000;
  // Create a mach port to receive the child task on.
  char machPortName[128];
  sprintf(machPortName, "ExceptionHandlerTest.%d", getpid());
  ReceivePort parent_recv_port(machPortName);

  // Give the child process a pipe to block on.
  int fds[2];
  ASSERT_EQ(0, pipe(fds));

  // Fork off a child process to dump.
  pid_t pid = fork();
  if (pid == 0) {
    // In the child process
    close(fds[1]);

    // Send parent process the task and thread ports.
    MachSendMessage child_message(0);
    child_message.AddDescriptor(mach_task_self());
    child_message.AddDescriptor(mach_thread_self());

    MachPortSender child_sender(machPortName);
    if (child_sender.SendMessage(child_message, kTimeoutMs) != KERN_SUCCESS)
      exit(1);

    // Wait for the parent process.
    uint8_t data;
    read(fds[0], &data, 1);
    exit(0);
  }
  // In the parent process.
  ASSERT_NE(-1, pid);
  close(fds[0]);

  // Read the child's task and thread ports.
  MachReceiveMessage child_message;
  ASSERT_EQ(KERN_SUCCESS,
	    parent_recv_port.WaitForMessage(&child_message, kTimeoutMs));
  mach_port_t child_task = child_message.GetTranslatedPort(0);
  mach_port_t child_thread = child_message.GetTranslatedPort(1);
  ASSERT_NE((mach_port_t)MACH_PORT_NULL, child_task);
  ASSERT_NE((mach_port_t)MACH_PORT_NULL, child_thread);

  // Write a minidump of the child process.
  bool result = ExceptionHandler::WriteMinidumpForChild(child_task,
                                                        child_thread,
                                                        tempDir.path(),
                                                        DumpNameMDCallback,
                                                        this);
  ASSERT_EQ(true, result);

  // Ensure that minidump file exists and is > 0 bytes.
  ASSERT_FALSE(lastDumpName.empty());
  struct stat st;
  ASSERT_EQ(0, stat(lastDumpName.c_str(), &st));
  ASSERT_LT(0, st.st_size);

  // Unblock child process
  uint8_t data = 1;
  (void)write(fds[1], &data, 1);

  // Child process should have exited with a zero status.
  int ret;
  ASSERT_EQ(pid, waitpid(pid, &ret, 0));
  EXPECT_NE(0, WIFEXITED(ret));
  EXPECT_EQ(0, WEXITSTATUS(ret));
}

// Test that memory around the instruction pointer is written
// to the dump as a MinidumpMemoryRegion.
TEST_F(ExceptionHandlerTest, InstructionPointerMemory) {
  // Give the child process a pipe to report back on.
  int fds[2];
  ASSERT_EQ(0, pipe(fds));

  // These are defined here so the parent can use them to check the
  // data from the minidump afterwards.
  const u_int32_t kMemorySize = 256;  // bytes
  const int kOffset = kMemorySize / 2;
  // This crashes with SIGILL on x86/x86-64/arm.
  const unsigned char instructions[] = { 0xff, 0xff, 0xff, 0xff };

  pid_t pid = fork();
  if (pid == 0) {
    close(fds[0]);
    ExceptionHandler eh(tempDir.path(), NULL, MDCallback, &fds[1], true, NULL);
    // Get some executable memory.
    char* memory =
      reinterpret_cast<char*>(mmap(NULL,
                                   kMemorySize,
                                   PROT_READ | PROT_WRITE | PROT_EXEC,
                                   MAP_PRIVATE | MAP_ANON,
                                   -1,
                                   0));
    if (!memory)
      exit(0);

    // Write some instructions that will crash. Put them in the middle
    // of the block of memory, because the minidump should contain 128
    // bytes on either side of the instruction pointer.
    memcpy(memory + kOffset, instructions, sizeof(instructions));

    // Now execute the instructions, which should crash.
    typedef void (*void_function)(void);
    void_function memory_function =
      reinterpret_cast<void_function>(memory + kOffset);
    memory_function();
    // not reached
    exit(1);
  }
  // In the parent process.
  ASSERT_NE(-1, pid);
  close(fds[1]);

  // Wait for the background process to return the minidump file.
  close(fds[1]);
  char minidump_file[PATH_MAX];
  ssize_t nbytes = read(fds[0], minidump_file, sizeof(minidump_file));
  ASSERT_NE(0, nbytes);
  // Ensure that minidump file exists and is > 0 bytes.
  struct stat st;
  ASSERT_EQ(0, stat(minidump_file, &st));
  ASSERT_LT(0, st.st_size);

  // Child process should have exited with a zero status.
  int ret;
  ASSERT_EQ(pid, waitpid(pid, &ret, 0));
  EXPECT_NE(0, WIFEXITED(ret));
  EXPECT_EQ(0, WEXITSTATUS(ret));

  // Read the minidump. Locate the exception record and the
  // memory list, and then ensure that there is a memory region
  // in the memory list that covers the instruction pointer from
  // the exception record.
  Minidump minidump(minidump_file);
  ASSERT_TRUE(minidump.Read());

  MinidumpException* exception = minidump.GetException();
  MinidumpMemoryList* memory_list = minidump.GetMemoryList();
  ASSERT_TRUE(exception);
  ASSERT_TRUE(memory_list);
  ASSERT_NE((unsigned int)0, memory_list->region_count());

  MinidumpContext* context = exception->GetContext();
  ASSERT_TRUE(context);

  u_int64_t instruction_pointer;
  ASSERT_TRUE(context->GetInstructionPointer(&instruction_pointer));

  MinidumpMemoryRegion* region =
    memory_list->GetMemoryRegionForAddress(instruction_pointer);
  EXPECT_TRUE(region);

  EXPECT_EQ(kMemorySize, region->GetSize());
  const u_int8_t* bytes = region->GetMemory();
  ASSERT_TRUE(bytes);

  u_int8_t prefix_bytes[kOffset];
  u_int8_t suffix_bytes[kMemorySize - kOffset - sizeof(instructions)];
  memset(prefix_bytes, 0, sizeof(prefix_bytes));
  memset(suffix_bytes, 0, sizeof(suffix_bytes));
  EXPECT_TRUE(memcmp(bytes, prefix_bytes, sizeof(prefix_bytes)) == 0);
  EXPECT_TRUE(memcmp(bytes + kOffset, instructions, sizeof(instructions)) == 0);
  EXPECT_TRUE(memcmp(bytes + kOffset + sizeof(instructions),
                     suffix_bytes, sizeof(suffix_bytes)) == 0);
}

// Test that the memory region around the instruction pointer is
// bounded correctly on the low end.
TEST_F(ExceptionHandlerTest, InstructionPointerMemoryMinBound) {
  // Give the child process a pipe to report back on.
  int fds[2];
  ASSERT_EQ(0, pipe(fds));

  // These are defined here so the parent can use them to check the
  // data from the minidump afterwards.
  const u_int32_t kMemorySize = 256;  // bytes
  const int kOffset = 0;
  // This crashes with SIGILL on x86/x86-64/arm.
  const unsigned char instructions[] = { 0xff, 0xff, 0xff, 0xff };

  pid_t pid = fork();
  if (pid == 0) {
    close(fds[0]);
    ExceptionHandler eh(tempDir.path(), NULL, MDCallback, &fds[1], true, NULL);
    // Get some executable memory.
    char* memory =
      reinterpret_cast<char*>(mmap(NULL,
                                   kMemorySize,
                                   PROT_READ | PROT_WRITE | PROT_EXEC,
                                   MAP_PRIVATE | MAP_ANON,
                                   -1,
                                   0));
    if (!memory)
      exit(0);

    // Write some instructions that will crash. Put them at the start
    // of the block of memory, to ensure that the memory bounding
    // works properly.
    memcpy(memory + kOffset, instructions, sizeof(instructions));
    
    // Now execute the instructions, which should crash.
    typedef void (*void_function)(void);
    void_function memory_function =
      reinterpret_cast<void_function>(memory + kOffset);
    memory_function();
    // not reached
    exit(1);
  }
  // In the parent process.
  ASSERT_NE(-1, pid);
  close(fds[1]);

  // Wait for the background process to return the minidump file.
  close(fds[1]);
  char minidump_file[PATH_MAX];
  ssize_t nbytes = read(fds[0], minidump_file, sizeof(minidump_file));
  ASSERT_NE(0, nbytes);
  // Ensure that minidump file exists and is > 0 bytes.
  struct stat st;
  ASSERT_EQ(0, stat(minidump_file, &st));
  ASSERT_LT(0, st.st_size);

  // Child process should have exited with a zero status.
  int ret;
  ASSERT_EQ(pid, waitpid(pid, &ret, 0));
  EXPECT_NE(0, WIFEXITED(ret));
  EXPECT_EQ(0, WEXITSTATUS(ret));

  // Read the minidump. Locate the exception record and the
  // memory list, and then ensure that there is a memory region
  // in the memory list that covers the instruction pointer from
  // the exception record.
  Minidump minidump(minidump_file);
  ASSERT_TRUE(minidump.Read());

  MinidumpException* exception = minidump.GetException();
  MinidumpMemoryList* memory_list = minidump.GetMemoryList();
  ASSERT_TRUE(exception);
  ASSERT_TRUE(memory_list);
  ASSERT_NE((unsigned int)0, memory_list->region_count());

  MinidumpContext* context = exception->GetContext();
  ASSERT_TRUE(context);

  u_int64_t instruction_pointer;
  ASSERT_TRUE(context->GetInstructionPointer(&instruction_pointer));

  MinidumpMemoryRegion* region =
    memory_list->GetMemoryRegionForAddress(instruction_pointer);
  EXPECT_TRUE(region);

  EXPECT_EQ(kMemorySize / 2, region->GetSize());
  const u_int8_t* bytes = region->GetMemory();
  ASSERT_TRUE(bytes);

  u_int8_t suffix_bytes[kMemorySize / 2 - sizeof(instructions)];
  memset(suffix_bytes, 0, sizeof(suffix_bytes));
  EXPECT_TRUE(memcmp(bytes + kOffset, instructions, sizeof(instructions)) == 0);
  EXPECT_TRUE(memcmp(bytes + kOffset + sizeof(instructions),
                     suffix_bytes, sizeof(suffix_bytes)) == 0);
}

// Test that the memory region around the instruction pointer is
// bounded correctly on the high end.
TEST_F(ExceptionHandlerTest, InstructionPointerMemoryMaxBound) {
  // Give the child process a pipe to report back on.
  int fds[2];
  ASSERT_EQ(0, pipe(fds));

  // These are defined here so the parent can use them to check the
  // data from the minidump afterwards.
  // Use 4k here because the OS will hand out a single page even
  // if a smaller size is requested, and this test wants to
  // test the upper bound of the memory range.
  const u_int32_t kMemorySize = 4096;  // bytes
  // This crashes with SIGILL on x86/x86-64/arm.
  const unsigned char instructions[] = { 0xff, 0xff, 0xff, 0xff };
  const int kOffset = kMemorySize - sizeof(instructions);

  pid_t pid = fork();
  if (pid == 0) {
    close(fds[0]);
    ExceptionHandler eh(tempDir.path(), NULL, MDCallback, &fds[1], true, NULL);
    // Get some executable memory.
    char* memory =
      reinterpret_cast<char*>(mmap(NULL,
                                   kMemorySize,
                                   PROT_READ | PROT_WRITE | PROT_EXEC,
                                   MAP_PRIVATE | MAP_ANON,
                                   -1,
                                   0));
    if (!memory)
      exit(0);

    // Write some instructions that will crash. Put them at the start
    // of the block of memory, to ensure that the memory bounding
    // works properly.
    memcpy(memory + kOffset, instructions, sizeof(instructions));
    
    // Now execute the instructions, which should crash.
    typedef void (*void_function)(void);
    void_function memory_function =
      reinterpret_cast<void_function>(memory + kOffset);
    memory_function();
    // not reached
    exit(1);
  }
  // In the parent process.
  ASSERT_NE(-1, pid);
  close(fds[1]);

  // Wait for the background process to return the minidump file.
  close(fds[1]);
  char minidump_file[PATH_MAX];
  ssize_t nbytes = read(fds[0], minidump_file, sizeof(minidump_file));
  ASSERT_NE(0, nbytes);
  // Ensure that minidump file exists and is > 0 bytes.
  struct stat st;
  ASSERT_EQ(0, stat(minidump_file, &st));
  ASSERT_LT(0, st.st_size);

  // Child process should have exited with a zero status.
  int ret;
  ASSERT_EQ(pid, waitpid(pid, &ret, 0));
  EXPECT_NE(0, WIFEXITED(ret));
  EXPECT_EQ(0, WEXITSTATUS(ret));

  // Read the minidump. Locate the exception record and the
  // memory list, and then ensure that there is a memory region
  // in the memory list that covers the instruction pointer from
  // the exception record.
  Minidump minidump(minidump_file);
  ASSERT_TRUE(minidump.Read());

  MinidumpException* exception = minidump.GetException();
  MinidumpMemoryList* memory_list = minidump.GetMemoryList();
  ASSERT_TRUE(exception);
  ASSERT_TRUE(memory_list);
  ASSERT_NE((unsigned int)0, memory_list->region_count());

  MinidumpContext* context = exception->GetContext();
  ASSERT_TRUE(context);

  u_int64_t instruction_pointer;
  ASSERT_TRUE(context->GetInstructionPointer(&instruction_pointer));

  MinidumpMemoryRegion* region =
    memory_list->GetMemoryRegionForAddress(instruction_pointer);
  EXPECT_TRUE(region);

  const size_t kPrefixSize = 128;  // bytes
  EXPECT_EQ(kPrefixSize + sizeof(instructions), region->GetSize());
  const u_int8_t* bytes = region->GetMemory();
  ASSERT_TRUE(bytes);

  u_int8_t prefix_bytes[kPrefixSize];
  memset(prefix_bytes, 0, sizeof(prefix_bytes));
  EXPECT_TRUE(memcmp(bytes, prefix_bytes, sizeof(prefix_bytes)) == 0);
  EXPECT_TRUE(memcmp(bytes + kPrefixSize,
                     instructions, sizeof(instructions)) == 0);
}

// Ensure that an extra memory block doesn't get added when the
// instruction pointer is not in mapped memory.
TEST_F(ExceptionHandlerTest, InstructionPointerMemoryNullPointer) {
  // Give the child process a pipe to report back on.
  int fds[2];
  ASSERT_EQ(0, pipe(fds));

  pid_t pid = fork();
  if (pid == 0) {
    close(fds[0]);
    ExceptionHandler eh(tempDir.path(), NULL, MDCallback, &fds[1], true, NULL);
    // Try calling a NULL pointer.
    typedef void (*void_function)(void);
    void_function memory_function =
      reinterpret_cast<void_function>(NULL);
    memory_function();
    // not reached
    exit(1);
  }
  // In the parent process.
  ASSERT_NE(-1, pid);
  close(fds[1]);

  // Wait for the background process to return the minidump file.
  close(fds[1]);
  char minidump_file[PATH_MAX];
  ssize_t nbytes = read(fds[0], minidump_file, sizeof(minidump_file));
  ASSERT_NE(0, nbytes);
  // Ensure that minidump file exists and is > 0 bytes.
  struct stat st;
  ASSERT_EQ(0, stat(minidump_file, &st));
  ASSERT_LT(0, st.st_size);

  // Child process should have exited with a zero status.
  int ret;
  ASSERT_EQ(pid, waitpid(pid, &ret, 0));
  EXPECT_NE(0, WIFEXITED(ret));
  EXPECT_EQ(0, WEXITSTATUS(ret));

  // Read the minidump. Locate the exception record and the
  // memory list, and then ensure that there is only one memory region
  // in the memory list (the thread memory from the single thread).
  Minidump minidump(minidump_file);
  ASSERT_TRUE(minidump.Read());

  MinidumpException* exception = minidump.GetException();
  MinidumpMemoryList* memory_list = minidump.GetMemoryList();
  ASSERT_TRUE(exception);
  ASSERT_TRUE(memory_list);
  ASSERT_EQ((unsigned int)1, memory_list->region_count());
}

static void *Junk(void *) {
  sleep(1000000);
  return NULL;
}

// Test that the memory list gets written correctly when multiple
// threads are running.
TEST_F(ExceptionHandlerTest, MemoryListMultipleThreads) {
  // Give the child process a pipe to report back on.
  int fds[2];
  ASSERT_EQ(0, pipe(fds));

  pid_t pid = fork();
  if (pid == 0) {
    close(fds[0]);
    ExceptionHandler eh(tempDir.path(), NULL, MDCallback, &fds[1], true, NULL);

    // Run an extra thread so >2 memory regions will be written.
    pthread_t junk_thread;
    if (pthread_create(&junk_thread, NULL, Junk, NULL) == 0)
      pthread_detach(junk_thread);

    // Just crash.
    Crasher();

    // not reached
    exit(1);
  }
  // In the parent process.
  ASSERT_NE(-1, pid);
  close(fds[1]);

  // Wait for the background process to return the minidump file.
  close(fds[1]);
  char minidump_file[PATH_MAX];
  ssize_t nbytes = read(fds[0], minidump_file, sizeof(minidump_file));
  ASSERT_NE(0, nbytes);
  // Ensure that minidump file exists and is > 0 bytes.
  struct stat st;
  ASSERT_EQ(0, stat(minidump_file, &st));
  ASSERT_LT(0, st.st_size);

  // Child process should have exited with a zero status.
  int ret;
  ASSERT_EQ(pid, waitpid(pid, &ret, 0));
  EXPECT_NE(0, WIFEXITED(ret));
  EXPECT_EQ(0, WEXITSTATUS(ret));

  // Read the minidump, and verify that the memory list can be read.
  Minidump minidump(minidump_file);
  ASSERT_TRUE(minidump.Read());

  MinidumpMemoryList* memory_list = minidump.GetMemoryList();
  ASSERT_TRUE(memory_list);
  // Verify that there are three memory regions:
  // one per thread, and one for the instruction pointer memory.
  ASSERT_EQ((unsigned int)3, memory_list->region_count());
}

}