Allow adding extra memory regions to minidump on linux/windows

A=Bill McCloskey <wmccloskey@mozilla.com>, ted, original patch from https://bugzilla.mozilla.org/show_bug.cgi?id=662646
R=mark at https://breakpad.appspot.com/450002/

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@1041 4c0a9323-5329-0410-9bdc-e9ce6186880e

src/client/linux/handler/exception_handler.cc

@@ -495,13 +495,15 @@ bool ExceptionHandler::DoDump(pid_t crashing_process, const void* context,
                                           crashing_process,
                                           context,
                                           context_size,
-                                          mapping_list_);
+                                          mapping_list_,
+                                          app_memory_list_);
   }
   return google_breakpad::WriteMinidump(minidump_descriptor_.path(),
                                         crashing_process,
                                         context,
                                         context_size,
-                                        mapping_list_);
+                                        mapping_list_,
+                                        app_memory_list_);
 }
 
 // static
@@ -562,4 +564,26 @@ void ExceptionHandler::AddMappingInfo(const string& name,
   mapping_list_.push_back(mapping);
 }
 
+void ExceptionHandler::RegisterAppMemory(void* ptr, size_t length) {
+  AppMemoryList::iterator iter =
+    std::find(app_memory_list_.begin(), app_memory_list_.end(), ptr);
+  if (iter != app_memory_list_.end()) {
+    // Don't allow registering the same pointer twice.
+    return;
+  }
+
+  AppMemory app_memory;
+  app_memory.ptr = ptr;
+  app_memory.length = length;
+  app_memory_list_.push_back(app_memory);
+}
+
+void ExceptionHandler::UnregisterAppMemory(void* ptr) {
+  AppMemoryList::iterator iter =
+    std::find(app_memory_list_.begin(), app_memory_list_.end(), ptr);
+  if (iter != app_memory_list_.end()) {
+    app_memory_list_.erase(iter);
+  }
+}
+
 }  // namespace google_breakpad

src/client/linux/handler/exception_handler.h

@@ -193,6 +193,13 @@ class ExceptionHandler {
                       size_t mapping_size,
                       size_t file_offset);
 
+  // Register a block of memory of length bytes starting at address ptr
+  // to be copied to the minidump when a crash happens.
+  void RegisterAppMemory(void* ptr, size_t length);
+
+  // Unregister a block of memory that was registered with RegisterAppMemory.
+  void UnregisterAppMemory(void* ptr);
+
   // Force signal handling for the specified signal.
   bool SimulateSignalDelivery(int sig);
  private:
@@ -238,6 +245,10 @@ class ExceptionHandler {
   // Callers can add extra info about mappings for cases where the
   // dumper code cannot extract enough information from /proc/<pid>/maps.
   MappingList mapping_list_;
+
+  // Callers can request additional memory regions to be included in
+  // the dump.
+  AppMemoryList app_memory_list_;
 };
 
 }  // namespace google_breakpad

src/client/linux/handler/exception_handler_unittest.cc

@@ -939,6 +939,85 @@ TEST(ExceptionHandlerTest, GenerateMultipleDumpsWithPath) {
   ASSERT_TRUE(minidump2.Read());
   unlink(minidump_2.path());
 
-  // We expect 2 distinct files.
+  // 2 distinct files should be produced.
   ASSERT_STRNE(minidump_1_path.c_str(), minidump_2_path.c_str());
 }
+
+// Test that an additional memory region can be added to the minidump.
+TEST(ExceptionHandlerTest, AdditionalMemory) {
+  const u_int32_t kMemorySize = sysconf(_SC_PAGESIZE);
+
+  // Get some heap memory.
+  u_int8_t* memory = new u_int8_t[kMemorySize];
+  const uintptr_t kMemoryAddress = reinterpret_cast<uintptr_t>(memory);
+  ASSERT_TRUE(memory);
+
+  // Stick some data into the memory so the contents can be verified.
+  for (u_int32_t i = 0; i < kMemorySize; ++i) {
+    memory[i] = i % 255;
+  }
+
+  AutoTempDir temp_dir;
+  ExceptionHandler handler(
+      MinidumpDescriptor(temp_dir.path()), NULL, NULL, NULL, true, -1);
+
+  // Add the memory region to the list of memory to be included.
+  handler.RegisterAppMemory(memory, kMemorySize);
+  handler.WriteMinidump();
+
+  const MinidumpDescriptor& minidump_desc = handler.minidump_descriptor();
+
+  // Read the minidump. Ensure that the memory region is present
+  Minidump minidump(minidump_desc.path());
+  ASSERT_TRUE(minidump.Read());
+
+  MinidumpMemoryList* dump_memory_list = minidump.GetMemoryList();
+  ASSERT_TRUE(dump_memory_list);
+  const MinidumpMemoryRegion* region =
+    dump_memory_list->GetMemoryRegionForAddress(kMemoryAddress);
+  ASSERT_TRUE(region);
+
+  EXPECT_EQ(kMemoryAddress, region->GetBase());
+  EXPECT_EQ(kMemorySize, region->GetSize());
+
+  // Verify memory contents.
+  EXPECT_EQ(0, memcmp(region->GetMemory(), memory, kMemorySize));
+
+  delete[] memory;
+}
+
+// Test that a memory region that was previously registered
+// can be unregistered.
+TEST(ExceptionHandlerTest, AdditionalMemoryRemove) {
+  const u_int32_t kMemorySize = sysconf(_SC_PAGESIZE);
+
+  // Get some heap memory.
+  u_int8_t* memory = new u_int8_t[kMemorySize];
+  const uintptr_t kMemoryAddress = reinterpret_cast<uintptr_t>(memory);
+  ASSERT_TRUE(memory);
+
+  AutoTempDir temp_dir;
+  ExceptionHandler handler(
+      MinidumpDescriptor(temp_dir.path()), NULL, NULL, NULL, true, -1);
+
+  // Add the memory region to the list of memory to be included.
+  handler.RegisterAppMemory(memory, kMemorySize);
+
+  // ...and then remove it
+  handler.UnregisterAppMemory(memory);
+  handler.WriteMinidump();
+
+  const MinidumpDescriptor& minidump_desc = handler.minidump_descriptor();
+
+  // Read the minidump. Ensure that the memory region is not present.
+  Minidump minidump(minidump_desc.path());
+  ASSERT_TRUE(minidump.Read());
+
+  MinidumpMemoryList* dump_memory_list = minidump.GetMemoryList();
+  ASSERT_TRUE(dump_memory_list);
+  const MinidumpMemoryRegion* region =
+    dump_memory_list->GetMemoryRegionForAddress(kMemoryAddress);
+  EXPECT_FALSE(region);
+
+  delete[] memory;
+}