Bug 1254779 - add tests to verify allocation function hooking; r=glandium
authorNathan Froyd <froydnj@gmail.com>
Fri, 12 Aug 2016 18:55:07 -0400
changeset 309322 acf0b272b695e7321c085d2da947f009855d0d2c
parent 309321 61adb42886fe0a010c1991fbb4078dd86f3dddf0
child 309323 0d47ee7e684e8dd7edd997b42dc34a7554adba5e
push id30561
push userkwierso@gmail.com
push dateMon, 15 Aug 2016 21:20:49 +0000
treeherdermozilla-central@91a319101587 [default view] [failures only]
perfherder[talos] [build metrics] [platform microbench] (compared to previous push)
reviewersglandium
bugs1254779
milestone51.0a1
first release with
nightly linux32
nightly linux64
nightly mac
nightly win32
nightly win64
last release without
nightly linux32
nightly linux64
nightly mac
nightly win32
nightly win64
Bug 1254779 - add tests to verify allocation function hooking; r=glandium
xpcom/tests/gtest/TestAllocReplacement.cpp
xpcom/tests/gtest/moz.build
new file mode 100644
--- /dev/null
+++ b/xpcom/tests/gtest/TestAllocReplacement.cpp
@@ -0,0 +1,175 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/Attributes.h"
+#include "mozilla/Function.h"
+#include "mozilla/mozalloc.h"
+#include "mozilla/ScopeExit.h"
+#include "nsCOMPtr.h"
+#include "nsIMemoryReporter.h"
+#include "nsServiceManagerUtils.h"
+#include "gtest/gtest.h"
+
+// We want to ensure that various functions are hooked properly and that
+// allocations are getting routed through jemalloc.  The strategy
+// pursued below relies on jemalloc's statistics tracking: we measure
+// the size of the jemalloc heap using nsIMemoryReporterManager,
+// allocate a chunk of memory with whatever function is supposed to be
+// hooked, and then ask for the size of the jemalloc heap again.  If the
+// function has been hooked correctly, then the heap size should be
+// different between the two measurements.  We can also check the
+// hooking of |free| and similar functions: once we free() the returned
+// pointer, we can measure the jemalloc heap size again, expecting it to
+// be identical to the size prior to the allocation.
+//
+// If we're not using jemalloc, then nsIMemoryReporterManager will
+// simply report an error, and we will ignore the entire test.
+//
+// This strategy is not perfect: it relies on GTests being
+// single-threaded, which they are, and no other threads doing
+// allocation during the test, which is uncertain, as XPCOM has started
+// up during gtests, and who knows what might be going on behind the
+// scenes.  This latter assumption, however, does not seem to be a
+// problem in practice.
+#if defined(MOZ_MEMORY)
+#define ALLOCATION_ASSERT(b) ASSERT_TRUE((b))
+#else
+#define ALLOCATION_ASSERT(b) (void)(b)
+#endif
+
+#define ASSERT_ALLOCATION_HAPPENED(lambda)      \
+  ALLOCATION_ASSERT(ValidateHookedAllocation(lambda, free));
+
+// We do run the risk of OOM'ing when we allocate something...all we can
+// do is try to allocate something so small that OOM'ing is unlikely.
+const size_t kAllocAmount = 16;
+
+// We declare this function MOZ_NEVER_INLINE to work around optimizing
+// compilers.  If we permitted inlining here, then the compiler might
+// inline both this function and the calls to the function pointers we
+// pass in, giving something like:
+//
+//   void* p = malloc(...);
+//   ...do nothing with p except check nullptr-ness...
+//   free(p);
+//
+// and the optimizer can delete the calls to malloc and free entirely,
+// which would make checking that the jemalloc heap had never changed
+// difficult.
+static MOZ_NEVER_INLINE bool
+ValidateHookedAllocation(void* (*aAllocator)(void),
+                         void (*aFreeFunction)(void*))
+{
+  nsCOMPtr<nsIMemoryReporterManager> manager =
+    do_GetService("@mozilla.org/memory-reporter-manager;1");
+
+  int64_t before = 0;
+  nsresult rv = manager->GetHeapAllocated(&before);
+  if (NS_FAILED(rv)) {
+    return false;
+  }
+
+  {
+    void* p = aAllocator();
+
+    if (!p) {
+      return false;
+    }
+
+    int64_t after = 0;
+    rv = manager->GetHeapAllocated(&after);
+
+    // Regardless of whether that call succeeded or failed, we are done with
+    // the allocated buffer now.
+    aFreeFunction(p);
+
+    if (NS_FAILED(rv)) {
+      return false;
+    }
+
+    // Verify that our heap stats have changed.
+    if ((before + int64_t(kAllocAmount)) != after) {
+      return false;
+    }
+  }
+
+  // Verify that freeing the allocated pointer resets our heap to what it
+  // was before.
+  int64_t after = 0;
+  rv = manager->GetHeapAllocated(&after);
+  if (NS_FAILED(rv)) {
+    return false;
+  }
+
+  return before == after;
+}
+
+TEST(AllocReplacement, malloc_check)
+{
+  ASSERT_ALLOCATION_HAPPENED([] {
+    return malloc(kAllocAmount);
+  });
+}
+
+TEST(AllocReplacement, calloc_check)
+{
+  ASSERT_ALLOCATION_HAPPENED([] {
+    return calloc(1, kAllocAmount);
+  });
+}
+
+TEST(AllocReplacement, realloc_check)
+{
+  ASSERT_ALLOCATION_HAPPENED([] {
+    return realloc(nullptr, kAllocAmount);
+  });
+}
+
+#if defined(HAVE_POSIX_MEMALIGN)
+TEST(AllocReplacement, posix_memalign_check)
+{
+  ASSERT_ALLOCATION_HAPPENED([] {
+    void* p = nullptr;
+    int result = posix_memalign(&p, sizeof(void*), kAllocAmount);
+    if (result != 0) {
+      return static_cast<void*>(nullptr);
+    }
+    return p;
+  });
+}
+#endif
+
+#if defined(XP_WIN)
+#include <windows.h>
+
+#undef ASSERT_ALLOCATION_HAPPENED
+#define ASSERT_ALLOCATION_HAPPENED(lambda)      \
+  ALLOCATION_ASSERT(ValidateHookedAllocation(lambda, [](void* p) { \
+    HeapFree(GetProcessHeap(), 0, p); \
+  }));
+
+TEST(AllocReplacement, HeapAlloc_check)
+{
+  ASSERT_ALLOCATION_HAPPENED([] {
+    HANDLE h = GetProcessHeap();
+    return HeapAlloc(h, 0, kAllocAmount);
+  });
+}
+
+TEST(AllocReplacement, HeapReAlloc_check)
+{
+  ASSERT_ALLOCATION_HAPPENED([] {
+    HANDLE h = GetProcessHeap();
+    void *p = HeapAlloc(h, 0, kAllocAmount / 2);
+
+    if (!p) {
+      return static_cast<void*>(nullptr);
+    }
+
+    return HeapReAlloc(h, 0, p, kAllocAmount);
+  });
+}
+#endif
--- a/xpcom/tests/gtest/moz.build
+++ b/xpcom/tests/gtest/moz.build
@@ -26,13 +26,19 @@ UNIFIED_SOURCES += [
     'TestThreadPool.cpp',
     'TestThreads.cpp',
     'TestTimeStamp.cpp',
     'TestTokenizer.cpp',
     'TestUTF.cpp',
     'TestXPIDLString.cpp',
 ]
 
+# Compile TestAllocReplacement separately so Windows headers don't pollute
+# the global namespace for other files.
+SOURCES += [
+    'TestAllocReplacement.cpp',
+]
+
 LOCAL_INCLUDES += [
     '../../base',
 ]
 
 FINAL_LIBRARY = 'xul-gtest'