The Tor Browser: security/sandbox/chromium/base/win/event_trace

security/sandbox/chromium/base/win/event_trace_provider.h@b8a032363ba2 (annotated)

security/sandbox/chromium/base/win/event_trace_provider.h

Thu, 22 Jan 2015 13:21:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 22 Jan 2015 13:21:57 +0100
branch: TOR_BUG_9701
changeset 15: b8a032363ba2
permissions: -rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
 // Declaration of a Windows event trace provider class, to allow using
 // Windows Event Tracing for logging transport and control.
 #ifndef BASE_WIN_EVENT_TRACE_PROVIDER_H_
 #define BASE_WIN_EVENT_TRACE_PROVIDER_H_
 #include <windows.h>
 #include <wmistr.h>
 #include <evntrace.h>
 #include "base/base_export.h"
 #include "base/basictypes.h"
 namespace base {
 namespace win {
 typedef GUID EtwEventClass;
 typedef UCHAR EtwEventType;
 typedef UCHAR EtwEventLevel;
 typedef USHORT EtwEventVersion;
 typedef ULONG EtwEventFlags;
 // Base class is a POD for correctness.
 template <size_t N> struct EtwMofEventBase {
   EVENT_TRACE_HEADER header;
   MOF_FIELD fields[N];
 };
 // Utility class to auto-initialize event trace header structures.
 template <size_t N> class EtwMofEvent: public EtwMofEventBase<N> {
  public:
   typedef EtwMofEventBase<N> Super;
   // Clang and the C++ standard don't allow unqualified lookup into dependent
   // bases, hence these using decls to explicitly pull the names out.
   using EtwMofEventBase<N>::header;
   using EtwMofEventBase<N>::fields;
   EtwMofEvent() {
     memset(static_cast<Super*>(this), 0, sizeof(Super));
   }
   EtwMofEvent(const EtwEventClass& event_class, EtwEventType type,
               EtwEventLevel level) {
     memset(static_cast<Super*>(this), 0, sizeof(Super));
     header.Size = sizeof(Super);
     header.Guid = event_class;
     header.Class.Type = type;
     header.Class.Level = level;
     header.Flags = WNODE_FLAG_TRACED_GUID | WNODE_FLAG_USE_MOF_PTR;
   }
   EtwMofEvent(const EtwEventClass& event_class, EtwEventType type,
               EtwEventVersion version, EtwEventLevel level) {
     memset(static_cast<Super*>(this), 0, sizeof(Super));
     header.Size = sizeof(Super);
     header.Guid = event_class;
     header.Class.Type = type;
     header.Class.Version = version;
     header.Class.Level = level;
     header.Flags = WNODE_FLAG_TRACED_GUID | WNODE_FLAG_USE_MOF_PTR;
   }
   void SetField(int field, size_t size, const void *data) {
     // DCHECK(field < N);
     if ((field < N) && (size <= kuint32max)) {
       fields[field].DataPtr = reinterpret_cast<ULONG64>(data);
       fields[field].Length = static_cast<ULONG>(size);
     }
   }
   EVENT_TRACE_HEADER* get() { return& header; }
  private:
   DISALLOW_COPY_AND_ASSIGN(EtwMofEvent);
 };
 // Trace provider with Event Tracing for Windows. The trace provider
 // registers with ETW by its name which is a GUID. ETW calls back to
 // the object whenever the trace level or enable flags for this provider
 // name changes.
 // Users of this class can test whether logging is currently enabled at
 // a particular trace level, and whether particular enable flags are set,
 // before other resources are consumed to generate and issue the log
 // messages themselves.
 class BASE_EXPORT EtwTraceProvider {
  public:
   // Creates an event trace provider identified by provider_name, which
   // will be the name registered with Event Tracing for Windows (ETW).
   explicit EtwTraceProvider(const GUID& provider_name);
   // Creates an unnamed event trace provider, the provider must be given
   // a name before registration.
   EtwTraceProvider();
   virtual ~EtwTraceProvider();
   // Registers the trace provider with Event Tracing for Windows.
   // Note: from this point forward ETW may call the provider's control
   //    callback. If the provider's name is enabled in some trace session
   //    already, the callback may occur recursively from this call, so
   //    call this only when you're ready to handle callbacks.
   ULONG Register();
   // Unregisters the trace provider with ETW.
   ULONG Unregister();
   // Accessors.
   void set_provider_name(const GUID& provider_name) {
     provider_name_ = provider_name;
   }
   const GUID& provider_name() const { return provider_name_; }
   TRACEHANDLE registration_handle() const { return registration_handle_; }
   TRACEHANDLE session_handle() const { return session_handle_; }
   EtwEventFlags enable_flags() const { return enable_flags_; }
   EtwEventLevel enable_level() const { return enable_level_; }
   // Returns true iff logging should be performed for "level" and "flags".
   // Note: flags is treated as a bitmask, and should normally have a single
   //      bit set, to test whether to log for a particular sub "facility".
   bool ShouldLog(EtwEventLevel level, EtwEventFlags flags) {
     return NULL != session_handle_ && level >= enable_level_ &&
         (0 != (flags & enable_flags_));
   }
   // Simple wrappers to log Unicode and ANSI strings.
   // Do nothing if !ShouldLog(level, 0xFFFFFFFF).
   ULONG Log(const EtwEventClass& event_class, EtwEventType type,
             EtwEventLevel level, const char *message);
   ULONG Log(const EtwEventClass& event_class, EtwEventType type,
             EtwEventLevel level, const wchar_t *message);
   // Log the provided event.
   ULONG Log(EVENT_TRACE_HEADER* event);
  protected:
   // Called after events have been enabled, override in subclasses
   // to set up state or log at the start of a session.
   // Note: This function may be called ETW's thread and may be racy,
   //    bring your own locking if needed.
   virtual void OnEventsEnabled() {}
   // Called just before events are disabled, override in subclasses
   // to tear down state or log at the end of a session.
   // Note: This function may be called ETW's thread and may be racy,
   //    bring your own locking if needed.
   virtual void OnEventsDisabled() {}
   // Called just after events have been disabled, override in subclasses
   // to tear down state at the end of a session. At this point it's
   // to late to log anything to the session.
   // Note: This function may be called ETW's thread and may be racy,
   //    bring your own locking if needed.
   virtual void PostEventsDisabled() {}
  private:
   ULONG EnableEvents(PVOID buffer);
   ULONG DisableEvents();
   ULONG Callback(WMIDPREQUESTCODE request, PVOID buffer);
   static ULONG WINAPI ControlCallback(WMIDPREQUESTCODE request, PVOID context,
                                       ULONG *reserved, PVOID buffer);
   GUID provider_name_;
   TRACEHANDLE registration_handle_;
   TRACEHANDLE session_handle_;
   EtwEventFlags enable_flags_;
   EtwEventLevel enable_level_;
   // We don't use this, but on XP we're obliged to pass one in to
   // RegisterTraceGuids. Non-const, because that's how the API needs it.
   static TRACE_GUID_REGISTRATION obligatory_guid_registration_;
   DISALLOW_COPY_AND_ASSIGN(EtwTraceProvider);
 };
 }  // namespace win
 }  // namespace base
 #endif  // BASE_WIN_EVENT_TRACE_PROVIDER_H_

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security/sandbox/chromium/base/win/event_trace_provider.h@b8a032363ba2 (annotated)

security/sandbox/chromium/base/win/event_trace_provider.h