crashpad client for windows

Introduces CrashpadClient::SetHandler()

The code in the cc plays it fast and loose but helps ground
the intention.

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

Review URL: https://codereview.chromium.org/1095273003

client/client.gyp

@@ -37,6 +37,7 @@
         'crash_report_database_win.cc',
         'crashpad_client.h',
         'crashpad_client_mac.cc',
+        'crashpad_client_win.cc',
         'crashpad_info.cc',
         'crashpad_info.h',
         'settings.cc',

client/crashpad_client.h

@@ -49,6 +49,9 @@ class CrashpadClient {
   //! send right corresponding to a receive right held by the handler process.
   //! The handler process runs an exception server on this port.
   //!
+  //! On Windows, SetHandler() is normally used instead since the handler is
+  //! started by other means.
+  //!
   //! \param[in] handler The path to a Crashpad handler executable.
   //! \param[in] database The path to a Crashpad database. The handler will be
   //!     started with this path as its `--database` argument.
@@ -69,9 +72,27 @@ class CrashpadClient {
                     const std::map<std::string, std::string>& annotations,
                     const std::vector<std::string>& arguments);
 
+#if defined(OS_WIN) || DOXYGEN
+  //! \brief Sets the IPC port of a presumably-running Crashpad handler process
+  //!     which was started with StartHandler() or by other compatible means
+  //!     and does an IPC message exchange to register this process with the
+  //!     handler. However, just like StartHandler(), crashes are not serviced
+  //!     until UseHandler() is called.
+  //!
+  //! The IPC port name (somehow) encodes enough information so that
+  //! registration is done with a crash handler using the appropriate database
+  //! and upload server.
+  //!
+  //! \param[in] ipc_port The full name of the crash handler IPC port.
+  //!
+  //! \return `true` on success and `false` on failure.
+  bool SetHandler(const std::string& ipc_port);
+#endif
+
   //! \brief Configures the process to direct its crashes to a Crashpad handler.
   //!
-  //! The Crashpad handler must previously have been started by StartHandler().
+  //! The Crashpad handler must previously have been started by StartHandler()
+  //! or configured by SetHandler().
   //!
   //! On Mac OS X, this method sets the task’s exception port for `EXC_CRASH`,
   //! `EXC_RESOURCE`, and `EXC_GUARD` exceptions to the Mach send right obtained
@@ -85,6 +106,10 @@ class CrashpadClient {
   //! have inherited it as their exception handler even after the process that
   //! called StartHandler() exits.
   //!
+  //! On Windows, this method sets the unhandled exception handler to a local
+  //! function that when reached will "signal and wait" for the crash handler
+  //! process to create the dump.
+  //!
   //! \return `true` on success, `false` on failure with a message logged.
   bool UseHandler();
 

client/crashpad_client_win.cc

@@ -0,0 +1,91 @@
+// 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 "client/crashpad_client.h"
+
+#include <windows.h>
+
+#include "base/logging.h"
+
+namespace {
+// Time to wait for the handler to create a dump. This is tricky to figure out.
+const DWORD kMillisecondsUntilTerminate = 5000;
+
+// This is the exit code that the process will return to the system once the
+// crash has been handled by Crashpad. We don't want to clash with the 
+// application-defined exit codes but we don't know them so we use one that is
+// unlikely to be used.
+const UINT kCrashExitCode = 0xffff7001;
+
+// These two handles to events are leaked.
+HANDLE g_signal_exception = nullptr;
+HANDLE g_wait_termination = nullptr;
+
+LONG WINAPI UnhandledExceptionHandler(EXCEPTION_POINTERS* exception_pointers) {
+  // TODO (cpu): Here write |exception_pointers| to g_crashpad_info.
+  DWORD rv = SignalObjectAndWait(g_signal_exception,
+                                 g_wait_termination,
+                                 kMillisecondsUntilTerminate,
+                                 FALSE);
+  if (rv != WAIT_OBJECT_0) {
+    // Something went wrong. It is likely that a dump has not been created.
+    if (rv == WAIT_TIMEOUT) {
+      LOG(WARNING) << "SignalObjectAndWait timed out";
+    } else {
+      PLOG(WARNING) << "SignalObjectAndWait error";
+    }
+  }
+  // We don't want to generate more exceptions, so we take the fast route.
+  TerminateProcess(GetCurrentProcess(), kCrashExitCode);
+  return 0L;
+}
+
+}  // namespace
+
+namespace crashpad {
+
+CrashpadClient::CrashpadClient() {
+}
+
+CrashpadClient::~CrashpadClient() {
+}
+
+bool CrashpadClient::StartHandler(
+    const base::FilePath& handler,
+    const base::FilePath& database,
+    const std::string& url,
+    const std::map<std::string, std::string>& annotations,
+    const std::vector<std::string>& arguments) {
+  // TODO(cpu): Provide a reference implementation.
+  return false;
+}
+
+bool SetHandler(const std::string& ipc_port) {
+  // TODO (cpu): Contact the handler and obtain g_signal_exception and
+  // g_wait_termination.
+  return false;
+}
+
+bool CrashpadClient::UseHandler() {
+  if (!g_signal_exception)
+    return false;
+  if (!g_wait_termination)
+    return false;
+  // In theory we could store the previous handler but it is not clear what
+  // use we have for it.
+  SetUnhandledExceptionFilter(&UnhandledExceptionHandler);
+  return true;
+}
+
+}  // namespace crashpad