Support storing information about what modules are loaded in the process.

base/debug/activity_tracker.h

 // Copyright 2016 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.
 
 // Activity tracking provides a low-overhead method of collecting information
 // about the state of the application for analysis both while it is running
 // and after it has terminated unexpectedly. Its primary purpose is to help
 // locate reasons the browser becomes unresponsive by providing insight into
 // what all the various threads and processes are (or were) doing.
 
@@ skipping 614 matching lines @@
  public:
   // Type identifiers used when storing in persistent memory so they can be
   // identified during extraction; the first 4 bytes of the SHA1 of the name
   // is used as a unique integer. A "version number" is added to the base
   // so that, if the structure of that object changes, stored older versions
   // will be safely ignored. These are public so that an external process
   // can recognize records of this type within an allocator.
   enum : uint32_t {
     kTypeIdActivityTracker = 0x5D7381AF + 3,   // SHA1(ActivityTracker) v3
     kTypeIdUserDataRecord = 0x615EDDD7 + 2,    // SHA1(UserDataRecord) v2
+    kTypeIdModulesRecord = 0x484E2E03 + 1,     // SHA1(ModulesRecord) v1
     kTypeIdGlobalLogMessage = 0x4CF434F9 + 1,  // SHA1(GlobalLogMessage) v1
     kTypeIdGlobalDataRecord = kTypeIdUserDataRecord + 1000,
 
     kTypeIdActivityTrackerFree = ~kTypeIdActivityTracker,
     kTypeIdUserDataRecordFree = ~kTypeIdUserDataRecord,
   };
 
+  struct ModuleInfo {
+    bool is_loaded = false;
+    uintptr_t address = 0;
+    size_t size = 0;
+    std::string file;
+    std::string version;
+    std::string identifier;
+    std::string debug_file;
+    std::string debug_identifier;
+  };
+
   // This is a thin wrapper around the thread-tracker's ScopedActivity that
   // accesses the global tracker to provide some of the information, notably
   // which thread-tracker to use. It is safe to create even if activity
   // tracking is not enabled.
   class BASE_EXPORT ScopedThreadActivity
       : public ThreadActivityTracker::ScopedActivity {
    public:
     ScopedThreadActivity(const void* program_counter,
                          const void* origin,
                          Activity::Type type,
@@ skipping 83 matching lines @@
   // Creates an activity-tracker for the current thread.
   ThreadActivityTracker* CreateTrackerForCurrentThread();
 
   // Releases the activity-tracker for the current thread (for testing only).
   void ReleaseTrackerForCurrentThreadForTesting();
 
   // Records a log message. The current implementation does NOT recycle these
   // only store critical messages such as FATAL ones.
   void RecordLogMessage(StringPiece message);
 
+  // Records a module load/unload event. This is safe to call multiple times
+  // even with the same information.
+  void RecordModuleInfo(const ModuleInfo& info);
+
   // Accesses the global data record for storing arbitrary key/value pairs.
   ActivityUserData& user_data() { return user_data_; }
 
  private:
   friend class ScopedThreadActivity;
   friend class ActivityTrackerTest;
 
   enum : int {
     // The maximum number of threads that can be tracked within a process. If
     // more than this number run concurrently, tracking of new ones may cease.
@@ skipping 56 matching lines @@
   base::Lock thread_tracker_allocator_lock_;
 
   // A caching memory allocator for user data attached to activity data.
   ActivityTrackerMemoryAllocator user_data_allocator_;
   base::Lock user_data_allocator_lock_;
 
   // An object for holding global arbitrary key value pairs. Values must always
   // be written from the main UI thread.
   ActivityUserData user_data_;
 
+  // A map of global module information, keyed by module path.
+  std::map<const std::string, PersistentMemoryAllocator::Reference> modules_;

[manzagop (departed), 2016/12/14 20:08:54]

I believe it's possible to have the same module loaded at multiple offsets. We
might need the key to be something like pair<base_address, string>.

[bcwhite, 2016/12/14 21:59:05]

That would be annoying.  How about we wait to see if it's a real problem before
addressing it?

[manzagop (departed), 2016/12/16 16:09:31]

Totally. :( IIRC Siggi said this is to be expected so minimally put a comment to
highlight this case. Shouldn't affect chrome modules though.

[bcwhite, 2016/12/16 18:35:15]

Done.  If it comes to it, I'll probably support multiple addresses in the
ModuleInfoRecord.

+  base::Lock modules_lock_;
+
   // The active global activity tracker.
   static GlobalActivityTracker* g_tracker_;
 
   DISALLOW_COPY_AND_ASSIGN(GlobalActivityTracker);
 };
 
 
 // Record entry in to and out of an arbitrary block of code.
 class BASE_EXPORT ScopedActivity
     : public GlobalActivityTracker::ScopedThreadActivity {
@@ skipping 117 matching lines @@
   ScopedProcessWaitActivity(const void* program_counter,
                             const base::Process* process);
   DISALLOW_COPY_AND_ASSIGN(ScopedProcessWaitActivity);
 };
 #endif
 
 }  // namespace debug
 }  // namespace base
 
 #endif  // BASE_DEBUG_ACTIVITY_TRACKER_H_