base/memory/shared_memory_unittest.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "base/basictypes.h"
   6 #include "base/memory/scoped_ptr.h"
   7 #include "base/memory/shared_memory.h"
   8 #include "base/process/kill.h"
   9 #include "base/rand_util.h"
  10 #include "base/strings/string_number_conversions.h"
  11 #include "base/sys_info.h"
  12 #include "base/test/multiprocess_test.h"
  13 #include "base/threading/platform_thread.h"
  14 #include "base/time/time.h"
  15 #include "testing/gtest/include/gtest/gtest.h"
  16 #include "testing/multiprocess_func_list.h"
  17
  18 #if defined(OS_MACOSX)
  19 #include "base/mac/scoped_nsautorelease_pool.h"
  20 #endif
  21
  22 #if defined(OS_POSIX)
  23 #include <errno.h>
  24 #include <fcntl.h>
  25 #include <sys/mman.h>
  26 #include <sys/stat.h>
  27 #include <sys/types.h>
  28 #include <unistd.h>
  29 #endif
  30
  31 #if defined(OS_WIN)
  32 #include "base/win/scoped_handle.h"
  33 #endif
  34
  35 static const int kNumThreads = 5;
  36 #if !defined(OS_IOS)  // iOS does not allow multiple processes.
  37 static const int kNumTasks = 5;
  38 #endif
  39
  40 namespace base {
  41
  42 namespace {
  43
  44 // Each thread will open the shared memory.  Each thread will take a different 4
  45 // byte int pointer, and keep changing it, with some small pauses in between.
  46 // Verify that each thread's value in the shared memory is always correct.
  47 class MultipleThreadMain : public PlatformThread::Delegate {
  48  public:
  49   explicit MultipleThreadMain(int16 id) : id_(id) {}
  50   virtual ~MultipleThreadMain() {}
  51
  52   static void CleanUp() {
  53     SharedMemory memory;
  54     memory.Delete(s_test_name_);
  55   }
  56
  57   // PlatformThread::Delegate interface.
  58   virtual void ThreadMain() OVERRIDE {
  59 #if defined(OS_MACOSX)
  60     mac::ScopedNSAutoreleasePool pool;
  61 #endif
  62     const uint32 kDataSize = 1024;
  63     SharedMemory memory;
  64     bool rv = memory.CreateNamed(s_test_name_, true, kDataSize);
  65     EXPECT_TRUE(rv);
  66     rv = memory.Map(kDataSize);
  67     EXPECT_TRUE(rv);
  68     int *ptr = static_cast<int*>(memory.memory()) + id_;
  69     EXPECT_EQ(0, *ptr);
  70
  71     for (int idx = 0; idx < 100; idx++) {
  72       *ptr = idx;
  73       PlatformThread::Sleep(base::TimeDelta::FromMilliseconds(1));
  74       EXPECT_EQ(*ptr, idx);
  75     }
  76     // Reset back to 0 for the next test that uses the same name.
  77     *ptr = 0;
  78
  79     memory.Close();
  80   }
  81
  82  private:
  83   int16 id_;
  84
  85   static const char* const s_test_name_;
  86
  87   DISALLOW_COPY_AND_ASSIGN(MultipleThreadMain);
  88 };
  89
  90 const char* const MultipleThreadMain::s_test_name_ =
  91     "SharedMemoryOpenThreadTest";
  92
  93 // TODO(port):
  94 // This test requires the ability to pass file descriptors between processes.
  95 // We haven't done that yet in Chrome for POSIX.
  96 #if defined(OS_WIN)
  97 // Each thread will open the shared memory.  Each thread will take the memory,
  98 // and keep changing it while trying to lock it, with some small pauses in
  99 // between. Verify that each thread's value in the shared memory is always
 100 // correct.
 101 class MultipleLockThread : public PlatformThread::Delegate {
 102  public:
 103   explicit MultipleLockThread(int id) : id_(id) {}
 104   virtual ~MultipleLockThread() {}
 105
 106   // PlatformThread::Delegate interface.
 107   virtual void ThreadMain() OVERRIDE {
 108     const uint32 kDataSize = sizeof(int);
 109     SharedMemoryHandle handle = NULL;
 110     {
 111       SharedMemory memory1;
 112       EXPECT_TRUE(memory1.CreateNamed("SharedMemoryMultipleLockThreadTest",
 113                                  true, kDataSize));
 114       EXPECT_TRUE(memory1.ShareToProcess(GetCurrentProcess(), &handle));
 115       // TODO(paulg): Implement this once we have a posix version of
 116       // SharedMemory::ShareToProcess.
 117       EXPECT_TRUE(true);
 118     }
 119
 120     SharedMemory memory2(handle, false);
 121     EXPECT_TRUE(memory2.Map(kDataSize));
 122     volatile int* const ptr = static_cast<int*>(memory2.memory());
 123
 124     for (int idx = 0; idx < 20; idx++) {
 125       memory2.Lock();
 126       int i = (id_ << 16) + idx;
 127       *ptr = i;
 128       PlatformThread::Sleep(TimeDelta::FromMilliseconds(1));
 129       EXPECT_EQ(*ptr, i);
 130       memory2.Unlock();
 131     }
 132
 133     memory2.Close();
 134   }
 135
 136  private:
 137   int id_;
 138
 139   DISALLOW_COPY_AND_ASSIGN(MultipleLockThread);
 140 };
 141 #endif
 142
 143 }  // namespace
 144
 145 // Android doesn't support SharedMemory::Open/Delete/
 146 // CreateNamed(openExisting=true)
 147 #if !defined(OS_ANDROID)
 148 TEST(SharedMemoryTest, OpenClose) {
 149   const uint32 kDataSize = 1024;
 150   std::string test_name = "SharedMemoryOpenCloseTest";
 151
 152   // Open two handles to a memory segment, confirm that they are mapped
 153   // separately yet point to the same space.
 154   SharedMemory memory1;
 155   bool rv = memory1.Delete(test_name);
 156   EXPECT_TRUE(rv);
 157   rv = memory1.Delete(test_name);
 158   EXPECT_TRUE(rv);
 159   rv = memory1.Open(test_name, false);
 160   EXPECT_FALSE(rv);
 161   rv = memory1.CreateNamed(test_name, false, kDataSize);
 162   EXPECT_TRUE(rv);
 163   rv = memory1.Map(kDataSize);
 164   EXPECT_TRUE(rv);
 165   SharedMemory memory2;
 166   rv = memory2.Open(test_name, false);
 167   EXPECT_TRUE(rv);
 168   rv = memory2.Map(kDataSize);
 169   EXPECT_TRUE(rv);
 170   EXPECT_NE(memory1.memory(), memory2.memory());  // Compare the pointers.
 171
 172   // Make sure we don't segfault. (it actually happened!)
 173   ASSERT_NE(memory1.memory(), static_cast<void*>(NULL));
 174   ASSERT_NE(memory2.memory(), static_cast<void*>(NULL));
 175
 176   // Write data to the first memory segment, verify contents of second.
 177   memset(memory1.memory(), '1', kDataSize);
 178   EXPECT_EQ(memcmp(memory1.memory(), memory2.memory(), kDataSize), 0);
 179
 180   // Close the first memory segment, and verify the second has the right data.
 181   memory1.Close();
 182   char *start_ptr = static_cast<char *>(memory2.memory());
 183   char *end_ptr = start_ptr + kDataSize;
 184   for (char* ptr = start_ptr; ptr < end_ptr; ptr++)
 185     EXPECT_EQ(*ptr, '1');
 186
 187   // Close the second memory segment.
 188   memory2.Close();
 189
 190   rv = memory1.Delete(test_name);
 191   EXPECT_TRUE(rv);
 192   rv = memory2.Delete(test_name);
 193   EXPECT_TRUE(rv);
 194 }
 195
 196 TEST(SharedMemoryTest, OpenExclusive) {
 197   const uint32 kDataSize = 1024;
 198   const uint32 kDataSize2 = 2048;
 199   std::ostringstream test_name_stream;
 200   test_name_stream << "SharedMemoryOpenExclusiveTest."
 201                    << Time::Now().ToDoubleT();
 202   std::string test_name = test_name_stream.str();
 203
 204   // Open two handles to a memory segment and check that open_existing works
 205   // as expected.
 206   SharedMemory memory1;
 207   bool rv = memory1.CreateNamed(test_name, false, kDataSize);
 208   EXPECT_TRUE(rv);
 209
 210   // Memory1 knows it's size because it created it.
 211   EXPECT_EQ(memory1.requested_size(), kDataSize);
 212
 213   rv = memory1.Map(kDataSize);
 214   EXPECT_TRUE(rv);
 215
 216   // The mapped memory1 must be at least the size we asked for.
 217   EXPECT_GE(memory1.mapped_size(), kDataSize);
 218
 219   // The mapped memory1 shouldn't exceed rounding for allocation granularity.
 220   EXPECT_LT(memory1.mapped_size(),
 221             kDataSize + base::SysInfo::VMAllocationGranularity());
 222
 223   memset(memory1.memory(), 'G', kDataSize);
 224
 225   SharedMemory memory2;
 226   // Should not be able to create if openExisting is false.
 227   rv = memory2.CreateNamed(test_name, false, kDataSize2);
 228   EXPECT_FALSE(rv);
 229
 230   // Should be able to create with openExisting true.
 231   rv = memory2.CreateNamed(test_name, true, kDataSize2);
 232   EXPECT_TRUE(rv);
 233
 234   // Memory2 shouldn't know the size because we didn't create it.
 235   EXPECT_EQ(memory2.requested_size(), 0U);
 236
 237   // We should be able to map the original size.
 238   rv = memory2.Map(kDataSize);
 239   EXPECT_TRUE(rv);
 240
 241   // The mapped memory2 must be at least the size of the original.
 242   EXPECT_GE(memory2.mapped_size(), kDataSize);
 243
 244   // The mapped memory2 shouldn't exceed rounding for allocation granularity.
 245   EXPECT_LT(memory2.mapped_size(),
 246             kDataSize2 + base::SysInfo::VMAllocationGranularity());
 247
 248   // Verify that opening memory2 didn't truncate or delete memory 1.
 249   char *start_ptr = static_cast<char *>(memory2.memory());
 250   char *end_ptr = start_ptr + kDataSize;
 251   for (char* ptr = start_ptr; ptr < end_ptr; ptr++) {
 252     EXPECT_EQ(*ptr, 'G');
 253   }
 254
 255   memory1.Close();
 256   memory2.Close();
 257
 258   rv = memory1.Delete(test_name);
 259   EXPECT_TRUE(rv);
 260 }
 261 #endif
 262
 263 // Create a set of N threads to each open a shared memory segment and write to
 264 // it. Verify that they are always reading/writing consistent data.
 265 TEST(SharedMemoryTest, MultipleThreads) {
 266   MultipleThreadMain::CleanUp();
 267   // On POSIX we have a problem when 2 threads try to create the shmem
 268   // (a file) at exactly the same time, since create both creates the
 269   // file and zerofills it.  We solve the problem for this unit test
 270   // (make it not flaky) by starting with 1 thread, then
 271   // intentionally don't clean up its shmem before running with
 272   // kNumThreads.
 273
 274   int threadcounts[] = { 1, kNumThreads };
 275   for (size_t i = 0; i < arraysize(threadcounts); i++) {
 276     int numthreads = threadcounts[i];
 277     scoped_ptr<PlatformThreadHandle[]> thread_handles;
 278     scoped_ptr<MultipleThreadMain*[]> thread_delegates;
 279
 280     thread_handles.reset(new PlatformThreadHandle[numthreads]);
 281     thread_delegates.reset(new MultipleThreadMain*[numthreads]);
 282
 283     // Spawn the threads.
 284     for (int16 index = 0; index < numthreads; index++) {
 285       PlatformThreadHandle pth;
 286       thread_delegates[index] = new MultipleThreadMain(index);
 287       EXPECT_TRUE(PlatformThread::Create(0, thread_delegates[index], &pth));
 288       thread_handles[index] = pth;
 289     }
 290
 291     // Wait for the threads to finish.
 292     for (int index = 0; index < numthreads; index++) {
 293       PlatformThread::Join(thread_handles[index]);
 294       delete thread_delegates[index];
 295     }
 296   }
 297   MultipleThreadMain::CleanUp();
 298 }
 299
 300 // TODO(port): this test requires the MultipleLockThread class
 301 // (defined above), which requires the ability to pass file
 302 // descriptors between processes.  We haven't done that yet in Chrome
 303 // for POSIX.
 304 #if defined(OS_WIN)
 305 // Create a set of threads to each open a shared memory segment and write to it
 306 // with the lock held. Verify that they are always reading/writing consistent
 307 // data.
 308 TEST(SharedMemoryTest, Lock) {
 309   PlatformThreadHandle thread_handles[kNumThreads];
 310   MultipleLockThread* thread_delegates[kNumThreads];
 311
 312   // Spawn the threads.
 313   for (int index = 0; index < kNumThreads; ++index) {
 314     PlatformThreadHandle pth;
 315     thread_delegates[index] = new MultipleLockThread(index);
 316     EXPECT_TRUE(PlatformThread::Create(0, thread_delegates[index], &pth));
 317     thread_handles[index] = pth;
 318   }
 319
 320   // Wait for the threads to finish.
 321   for (int index = 0; index < kNumThreads; ++index) {
 322     PlatformThread::Join(thread_handles[index]);
 323     delete thread_delegates[index];
 324   }
 325 }
 326 #endif
 327
 328 // Allocate private (unique) shared memory with an empty string for a
 329 // name.  Make sure several of them don't point to the same thing as
 330 // we might expect if the names are equal.
 331 TEST(SharedMemoryTest, AnonymousPrivate) {
 332   int i, j;
 333   int count = 4;
 334   bool rv;
 335   const uint32 kDataSize = 8192;
 336
 337   scoped_ptr<SharedMemory[]> memories(new SharedMemory[count]);
 338   scoped_ptr<int*[]> pointers(new int*[count]);
 339   ASSERT_TRUE(memories.get());
 340   ASSERT_TRUE(pointers.get());
 341
 342   for (i = 0; i < count; i++) {
 343     rv = memories[i].CreateAndMapAnonymous(kDataSize);
 344     EXPECT_TRUE(rv);
 345     int *ptr = static_cast<int*>(memories[i].memory());
 346     EXPECT_TRUE(ptr);
 347     pointers[i] = ptr;
 348   }
 349
 350   for (i = 0; i < count; i++) {
 351     // zero out the first int in each except for i; for that one, make it 100.
 352     for (j = 0; j < count; j++) {
 353       if (i == j)
 354         pointers[j][0] = 100;
 355       else
 356         pointers[j][0] = 0;
 357     }
 358     // make sure there is no bleeding of the 100 into the other pointers
 359     for (j = 0; j < count; j++) {
 360       if (i == j)
 361         EXPECT_EQ(100, pointers[j][0]);
 362       else
 363         EXPECT_EQ(0, pointers[j][0]);
 364     }
 365   }
 366
 367   for (int i = 0; i < count; i++) {
 368     memories[i].Close();
 369   }
 370 }
 371
 372 TEST(SharedMemoryTest, ShareReadOnly) {
 373   StringPiece contents = "Hello World";
 374
 375   SharedMemory writable_shmem;
 376   ASSERT_TRUE(writable_shmem.CreateAndMapAnonymous(contents.size()));
 377   memcpy(writable_shmem.memory(), contents.data(), contents.size());
 378   EXPECT_TRUE(writable_shmem.Unmap());
 379
 380   SharedMemoryHandle readonly_handle;
 381   ASSERT_TRUE(writable_shmem.ShareReadOnlyToProcess(GetCurrentProcessHandle(),
 382                                                     &readonly_handle));
 383   SharedMemory readonly_shmem(readonly_handle, /*readonly=*/true);
 384
 385   ASSERT_TRUE(readonly_shmem.Map(contents.size()));
 386   EXPECT_EQ(contents,
 387             StringPiece(static_cast<const char*>(readonly_shmem.memory()),
 388                         contents.size()));
 389   EXPECT_TRUE(readonly_shmem.Unmap());
 390
 391   // Make sure the writable instance is still writable.
 392   ASSERT_TRUE(writable_shmem.Map(contents.size()));
 393   StringPiece new_contents = "Goodbye";
 394   memcpy(writable_shmem.memory(), new_contents.data(), new_contents.size());
 395   EXPECT_EQ(new_contents,
 396             StringPiece(static_cast<const char*>(writable_shmem.memory()),
 397                         new_contents.size()));
 398
 399   // We'd like to check that if we send the read-only segment to another
 400   // process, then that other process can't reopen it read/write.  (Since that
 401   // would be a security hole.)  Setting up multiple processes is hard in a
 402   // unittest, so this test checks that the *current* process can't reopen the
 403   // segment read/write.  I think the test here is stronger than we actually
 404   // care about, but there's a remote possibility that sending a file over a
 405   // pipe would transform it into read/write.
 406   SharedMemoryHandle handle = readonly_shmem.handle();
 407
 408 #if defined(OS_ANDROID)
 409   // The "read-only" handle is still writable on Android:
 410   // http://crbug.com/320865
 411   (void)handle;
 412 #elif defined(OS_POSIX)
 413   EXPECT_EQ(O_RDONLY, fcntl(handle.fd, F_GETFL) & O_ACCMODE)
 414       << "The descriptor itself should be read-only.";
 415
 416   errno = 0;
 417   void* writable = mmap(
 418       NULL, contents.size(), PROT_READ | PROT_WRITE, MAP_SHARED, handle.fd, 0);
 419   int mmap_errno = errno;
 420   EXPECT_EQ(MAP_FAILED, writable)
 421       << "It shouldn't be possible to re-mmap the descriptor writable.";
 422   EXPECT_EQ(EACCES, mmap_errno) << strerror(mmap_errno);
 423   if (writable != MAP_FAILED)
 424     EXPECT_EQ(0, munmap(writable, readonly_shmem.mapped_size()));
 425
 426 #elif defined(OS_WIN)
 427   EXPECT_EQ(NULL, MapViewOfFile(handle, FILE_MAP_WRITE, 0, 0, 0))
 428       << "Shouldn't be able to map memory writable.";
 429
 430   HANDLE temp_handle;
 431   BOOL rv = ::DuplicateHandle(GetCurrentProcess(),
 432                               handle,
 433                               GetCurrentProcess,
 434                               &temp_handle,
 435                               FILE_MAP_ALL_ACCESS,
 436                               false,
 437                               0);
 438   EXPECT_EQ(FALSE, rv)
 439       << "Shouldn't be able to duplicate the handle into a writable one.";
 440   if (rv)
 441     base::win::ScopedHandle writable_handle(temp_handle);
 442 #else
 443 #error Unexpected platform; write a test that tries to make 'handle' writable.
 444 #endif  // defined(OS_POSIX) || defined(OS_WIN)
 445 }
 446
 447 TEST(SharedMemoryTest, ShareToSelf) {
 448   StringPiece contents = "Hello World";
 449
 450   SharedMemory shmem;
 451   ASSERT_TRUE(shmem.CreateAndMapAnonymous(contents.size()));
 452   memcpy(shmem.memory(), contents.data(), contents.size());
 453   EXPECT_TRUE(shmem.Unmap());
 454
 455   SharedMemoryHandle shared_handle;
 456   ASSERT_TRUE(shmem.ShareToProcess(GetCurrentProcessHandle(), &shared_handle));
 457   SharedMemory shared(shared_handle, /*readonly=*/false);
 458
 459   ASSERT_TRUE(shared.Map(contents.size()));
 460   EXPECT_EQ(
 461       contents,
 462       StringPiece(static_cast<const char*>(shared.memory()), contents.size()));
 463
 464   ASSERT_TRUE(shmem.ShareToProcess(GetCurrentProcessHandle(), &shared_handle));
 465   SharedMemory readonly(shared_handle, /*readonly=*/true);
 466
 467   ASSERT_TRUE(readonly.Map(contents.size()));
 468   EXPECT_EQ(contents,
 469             StringPiece(static_cast<const char*>(readonly.memory()),
 470                         contents.size()));
 471 }
 472
 473 TEST(SharedMemoryTest, MapAt) {
 474   ASSERT_TRUE(SysInfo::VMAllocationGranularity() >= sizeof(uint32));
 475   const size_t kCount = SysInfo::VMAllocationGranularity();
 476   const size_t kDataSize = kCount * sizeof(uint32);
 477
 478   SharedMemory memory;
 479   ASSERT_TRUE(memory.CreateAndMapAnonymous(kDataSize));
 480   ASSERT_TRUE(memory.Map(kDataSize));
 481   uint32* ptr = static_cast<uint32*>(memory.memory());
 482   ASSERT_NE(ptr, static_cast<void*>(NULL));
 483
 484   for (size_t i = 0; i < kCount; ++i) {
 485     ptr[i] = i;
 486   }
 487
 488   memory.Unmap();
 489
 490   off_t offset = SysInfo::VMAllocationGranularity();
 491   ASSERT_TRUE(memory.MapAt(offset, kDataSize - offset));
 492   offset /= sizeof(uint32);
 493   ptr = static_cast<uint32*>(memory.memory());
 494   ASSERT_NE(ptr, static_cast<void*>(NULL));
 495   for (size_t i = offset; i < kCount; ++i) {
 496     EXPECT_EQ(ptr[i - offset], i);
 497   }
 498 }
 499
 500 #if defined(OS_POSIX)
 501 // Create a shared memory object, mmap it, and mprotect it to PROT_EXEC.
 502 TEST(SharedMemoryTest, AnonymousExecutable) {
 503   const uint32 kTestSize = 1 << 16;
 504
 505   SharedMemory shared_memory;
 506   SharedMemoryCreateOptions options;
 507   options.size = kTestSize;
 508   options.executable = true;
 509
 510   EXPECT_TRUE(shared_memory.Create(options));
 511   EXPECT_TRUE(shared_memory.Map(shared_memory.requested_size()));
 512
 513   EXPECT_EQ(0, mprotect(shared_memory.memory(), shared_memory.requested_size(),
 514                         PROT_READ | PROT_EXEC));
 515 }
 516
 517 // Android supports a different permission model than POSIX for its "ashmem"
 518 // shared memory implementation. So the tests about file permissions are not
 519 // included on Android.
 520 #if !defined(OS_ANDROID)
 521
 522 // Set a umask and restore the old mask on destruction.
 523 class ScopedUmaskSetter {
 524  public:
 525   explicit ScopedUmaskSetter(mode_t target_mask) {
 526     old_umask_ = umask(target_mask);
 527   }
 528   ~ScopedUmaskSetter() { umask(old_umask_); }
 529  private:
 530   mode_t old_umask_;
 531   DISALLOW_IMPLICIT_CONSTRUCTORS(ScopedUmaskSetter);
 532 };
 533
 534 // Create a shared memory object, check its permissions.
 535 TEST(SharedMemoryTest, FilePermissionsAnonymous) {
 536   const uint32 kTestSize = 1 << 8;
 537
 538   SharedMemory shared_memory;
 539   SharedMemoryCreateOptions options;
 540   options.size = kTestSize;
 541   // Set a file mode creation mask that gives all permissions.
 542   ScopedUmaskSetter permissive_mask(S_IWGRP | S_IWOTH);
 543
 544   EXPECT_TRUE(shared_memory.Create(options));
 545
 546   int shm_fd = shared_memory.handle().fd;
 547   struct stat shm_stat;
 548   EXPECT_EQ(0, fstat(shm_fd, &shm_stat));
 549   // Neither the group, nor others should be able to read the shared memory
 550   // file.
 551   EXPECT_FALSE(shm_stat.st_mode & S_IRWXO);
 552   EXPECT_FALSE(shm_stat.st_mode & S_IRWXG);
 553 }
 554
 555 // Create a shared memory object, check its permissions.
 556 TEST(SharedMemoryTest, FilePermissionsNamed) {
 557   const uint32 kTestSize = 1 << 8;
 558
 559   SharedMemory shared_memory;
 560   SharedMemoryCreateOptions options;
 561   options.size = kTestSize;
 562   std::string shared_mem_name = "shared_perm_test-" + IntToString(getpid()) +
 563       "-" + Uint64ToString(RandUint64());
 564   options.name = &shared_mem_name;
 565   // Set a file mode creation mask that gives all permissions.
 566   ScopedUmaskSetter permissive_mask(S_IWGRP | S_IWOTH);
 567
 568   EXPECT_TRUE(shared_memory.Create(options));
 569   // Clean-up the backing file name immediately, we don't need it.
 570   EXPECT_TRUE(shared_memory.Delete(shared_mem_name));
 571
 572   int shm_fd = shared_memory.handle().fd;
 573   struct stat shm_stat;
 574   EXPECT_EQ(0, fstat(shm_fd, &shm_stat));
 575   // Neither the group, nor others should have been able to open the shared
 576   // memory file while its name existed.
 577   EXPECT_FALSE(shm_stat.st_mode & S_IRWXO);
 578   EXPECT_FALSE(shm_stat.st_mode & S_IRWXG);
 579 }
 580 #endif  // !defined(OS_ANDROID)
 581
 582 #endif  // defined(OS_POSIX)
 583
 584 // Map() will return addresses which are aligned to the platform page size, this
 585 // varies from platform to platform though.  Since we'd like to advertise a
 586 // minimum alignment that callers can count on, test for it here.
 587 TEST(SharedMemoryTest, MapMinimumAlignment) {
 588   static const int kDataSize = 8192;
 589
 590   SharedMemory shared_memory;
 591   ASSERT_TRUE(shared_memory.CreateAndMapAnonymous(kDataSize));
 592   EXPECT_EQ(0U, reinterpret_cast<uintptr_t>(
 593       shared_memory.memory()) & (SharedMemory::MAP_MINIMUM_ALIGNMENT - 1));
 594   shared_memory.Close();
 595 }
 596
 597 #if !defined(OS_IOS)  // iOS does not allow multiple processes.
 598
 599 // On POSIX it is especially important we test shmem across processes,
 600 // not just across threads.  But the test is enabled on all platforms.
 601 class SharedMemoryProcessTest : public MultiProcessTest {
 602  public:
 603
 604   static void CleanUp() {
 605     SharedMemory memory;
 606     memory.Delete(s_test_name_);
 607   }
 608
 609   static int TaskTestMain() {
 610     int errors = 0;
 611 #if defined(OS_MACOSX)
 612     mac::ScopedNSAutoreleasePool pool;
 613 #endif
 614     const uint32 kDataSize = 1024;
 615     SharedMemory memory;
 616     bool rv = memory.CreateNamed(s_test_name_, true, kDataSize);
 617     EXPECT_TRUE(rv);
 618     if (rv != true)
 619       errors++;
 620     rv = memory.Map(kDataSize);
 621     EXPECT_TRUE(rv);
 622     if (rv != true)
 623       errors++;
 624     int *ptr = static_cast<int*>(memory.memory());
 625
 626     for (int idx = 0; idx < 20; idx++) {
 627       memory.Lock();
 628       int i = (1 << 16) + idx;
 629       *ptr = i;
 630       PlatformThread::Sleep(TimeDelta::FromMilliseconds(10));
 631       if (*ptr != i)
 632         errors++;
 633       memory.Unlock();
 634     }
 635
 636     memory.Close();
 637     return errors;
 638   }
 639
 640  private:
 641   static const char* const s_test_name_;
 642 };
 643
 644 const char* const SharedMemoryProcessTest::s_test_name_ = "MPMem";
 645
 646 TEST_F(SharedMemoryProcessTest, Tasks) {
 647   SharedMemoryProcessTest::CleanUp();
 648
 649   ProcessHandle handles[kNumTasks];
 650   for (int index = 0; index < kNumTasks; ++index) {
 651     handles[index] = SpawnChild("SharedMemoryTestMain", false);
 652     ASSERT_TRUE(handles[index]);
 653   }
 654
 655   int exit_code = 0;
 656   for (int index = 0; index < kNumTasks; ++index) {
 657     EXPECT_TRUE(WaitForExitCode(handles[index], &exit_code));
 658     EXPECT_EQ(0, exit_code);
 659   }
 660
 661   SharedMemoryProcessTest::CleanUp();
 662 }
 663
 664 MULTIPROCESS_TEST_MAIN(SharedMemoryTestMain) {
 665   return SharedMemoryProcessTest::TaskTestMain();
 666 }
 667
 668 #endif  // !OS_IOS
 669
 670 }  // namespace base