win: Implement and use ScopedProcessSuspend

R=mark@chromium.org
BUG=crashpad:1

Review URL: https://codereview.chromium.org/1303173011 .

handler/win/crash_report_exception_handler.cc

@@ -21,6 +21,7 @@
 #include "snapshot/win/process_snapshot_win.h"
 #include "util/file/file_writer.h"
 #include "util/win/registration_protocol_win.h"
+#include "util/win/scoped_process_suspend.h"
 
 namespace crashpad {
 
@@ -44,7 +45,7 @@ unsigned int CrashReportExceptionHandler::ExceptionHandlerServerException(
     WinVMAddress exception_information_address) {
   const unsigned int kFailedTerminationCode = 0xffff7002;
 
-  // TODO(scottmg): ScopedProcessSuspend
+  ScopedProcessSuspend suspend(process);
 
   ProcessSnapshotWin process_snapshot;
   if (!process_snapshot.Initialize(process)) {

tools/generate_dump.cc

@@ -41,6 +41,7 @@
 #elif defined(OS_WIN)
 #include "base/strings/utf_string_conversions.h"
 #include "snapshot/win/process_snapshot_win.h"
+#include "util/win/scoped_process_suspend.h"
 #endif  // OS_MACOSX
 
 namespace crashpad {
@@ -168,9 +169,9 @@ int GenerateDumpMain(int argc, char* argv[]) {
       suspend.reset(new ScopedTaskSuspend(task));
     }
 #elif defined(OS_WIN)
+    scoped_ptr<ScopedProcessSuspend> suspend;
     if (options.suspend) {
-      LOG(ERROR) << "TODO(scottmg): --no-suspend is required for now.";
-      return EXIT_FAILURE;
+      suspend.reset(new ScopedProcessSuspend(process.get()));
     }
 #endif  // OS_MACOSX
 

util/util.gyp

@@ -162,6 +162,8 @@
         'win/registration_protocol_win.h',
         'win/scoped_handle.cc',
         'win/scoped_handle.h',
+        'win/scoped_process_suspend.cc',
+        'win/scoped_process_suspend.h',
         'win/time.cc',
         'win/time.h',
       ],

util/util_test.gyp

@@ -81,6 +81,7 @@
         'thread/thread_test.cc',
         'win/exception_handler_server_test.cc',
         'win/process_info_test.cc',
+        'win/scoped_process_suspend_test.cc',
         'win/time_test.cc',
       ],
       'conditions': [

util/win/scoped_process_suspend.cc

@@ -0,0 +1,41 @@
+// Copyright 2015 The Crashpad Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "util/win/scoped_process_suspend.h"
+
+#include <winternl.h>
+
+#include "base/logging.h"
+
+namespace crashpad {
+
+ScopedProcessSuspend::ScopedProcessSuspend(HANDLE process) : process_(process) {
+  typedef NTSTATUS(__stdcall * NtSuspendProcessFunc)(HANDLE);
+  static NtSuspendProcessFunc func = reinterpret_cast<NtSuspendProcessFunc>(
+      GetProcAddress(GetModuleHandle(L"ntdll.dll"), "NtSuspendProcess"));
+  NTSTATUS status = func(process_);
+  if (status)
+    LOG(ERROR) << "NtSuspendProcess, ntstatus=" << status;
+}
+
+ScopedProcessSuspend::~ScopedProcessSuspend() {
+  typedef NTSTATUS(__stdcall * NtResumeProcessFunc)(HANDLE);
+  static NtResumeProcessFunc func = reinterpret_cast<NtResumeProcessFunc>(
+      GetProcAddress(GetModuleHandle(L"ntdll.dll"), "NtResumeProcess"));
+  NTSTATUS status = func(process_);
+  if (status)
+    LOG(ERROR) << "NtResumeProcess, ntstatus=" << status;
+}
+
+}  // namespace crashpad

util/win/scoped_process_suspend.h

@@ -0,0 +1,46 @@
+// Copyright 2015 The Crashpad Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef CRASHPAD_UTIL_WIN_SCOPED_PROCESS_SUSPEND_H_
+#define CRASHPAD_UTIL_WIN_SCOPED_PROCESS_SUSPEND_H_
+
+#include <windows.h>
+
+#include "base/basictypes.h"
+
+namespace crashpad {
+
+//! \brief Manages the suspension of another process.
+//!
+//! While an object of this class exists, the other process will be suspended.
+//! Once the object is destroyed, the other process will become eligible for
+//! resumption.
+//!
+//! If this process crashes while this object exists, there is no guarantee that
+//! the other process will be resumed.
+class ScopedProcessSuspend {
+ public:
+  //! Does not take ownership of \a process.
+  explicit ScopedProcessSuspend(HANDLE process);
+  ~ScopedProcessSuspend();
+
+ private:
+  HANDLE process_;
+
+  DISALLOW_COPY_AND_ASSIGN(ScopedProcessSuspend);
+};
+
+}  // namespace crashpad
+
+#endif  // CRASHPAD_UTIL_WIN_SCOPED_PROCESS_SUSPEND_H_

util/win/scoped_process_suspend_test.cc

@@ -0,0 +1,106 @@
+// Copyright 2015 The Crashpad Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "util/win/scoped_process_suspend.h"
+
+#include <tlhelp32.h>
+
+#include <algorithm>
+#include <vector>
+
+#include "gtest/gtest.h"
+#include "test/win/win_child_process.h"
+
+namespace crashpad {
+namespace test {
+namespace {
+
+// There is no per-process suspend count on Windows, only a per-thread suspend
+// count. NtSuspendProcess just suspends all threads of a given process. So,
+// verify that all thread's suspend counts match the desired suspend count.
+bool SuspendCountMatches(HANDLE process, DWORD desired_suspend_count) {
+  DWORD process_id = GetProcessId(process);
+
+  ScopedKernelHANDLE snapshot(CreateToolhelp32Snapshot(TH32CS_SNAPTHREAD, 0));
+  if (!snapshot.is_valid())
+    return false;
+
+  THREADENTRY32 te;
+  te.dwSize = sizeof(te);
+  if (!Thread32First(snapshot.get(), &te))
+    return false;
+  do {
+    if (te.dwSize >= offsetof(THREADENTRY32, th32OwnerProcessID) +
+                         sizeof(te.th32OwnerProcessID) &&
+        te.th32OwnerProcessID == process_id) {
+      ScopedKernelHANDLE thread(
+          OpenThread(THREAD_ALL_ACCESS, false, te.th32ThreadID));
+      DWORD result = SuspendThread(thread.get());
+      EXPECT_NE(result, static_cast<DWORD>(-1));
+      if (result != static_cast<DWORD>(-1))
+        ResumeThread(thread.get());
+      if (result != desired_suspend_count)
+        return false;
+    }
+    te.dwSize = sizeof(te);
+  } while (Thread32Next(snapshot.get(), &te));
+
+  return true;
+}
+
+class ScopedProcessSuspendTest final : public WinChildProcess {
+ public:
+  ScopedProcessSuspendTest() : WinChildProcess() {}
+  ~ScopedProcessSuspendTest() {}
+
+ private:
+  int Run() override {
+    char c;
+    // Wait for notification from parent.
+    EXPECT_TRUE(LoggingReadFile(ReadPipeHandle(), &c, sizeof(c)));
+    EXPECT_EQ(' ', c);
+    return EXIT_SUCCESS;
+  }
+
+  DISALLOW_COPY_AND_ASSIGN(ScopedProcessSuspendTest);
+};
+
+TEST(ScopedProcessSuspend, ScopedProcessSuspend) {
+  WinChildProcess::EntryPoint<ScopedProcessSuspendTest>();
+  scoped_ptr<WinChildProcess::Handles> handles = WinChildProcess::Launch();
+
+  EXPECT_TRUE(SuspendCountMatches(handles->process.get(), 0));
+
+  {
+    ScopedProcessSuspend suspend(handles->process.get());
+    EXPECT_TRUE(SuspendCountMatches(handles->process.get(), 1));
+
+    {
+      ScopedProcessSuspend suspend(handles->process.get());
+      EXPECT_TRUE(SuspendCountMatches(handles->process.get(), 2));
+    }
+
+    EXPECT_TRUE(SuspendCountMatches(handles->process.get(), 1));
+  }
+
+  EXPECT_TRUE(SuspendCountMatches(handles->process.get(), 0));
+
+  // Tell the child it's OK to terminate.
+  char c = ' ';
+  EXPECT_TRUE(WriteFile(handles->write.get(), &c, sizeof(c)));
+}
+
+}  // namespace
+}  // namespace test
+}  // namespace crashpad