Code to collect issue 97285 debugging info for crash reports.

chrome/app/chrome_main_delegate.cc

Index: chrome/app/chrome_main_delegate.cc
diff --git a/chrome/app/chrome_main_delegate.cc b/chrome/app/chrome_main_delegate.cc
index a1eaf52fb5ad84d823e1e74629451b29df8f7dcd..e6eb9a7035fcb9e52efa4a4cb56363fc6e958c4c 100644
--- a/chrome/app/chrome_main_delegate.cc
+++ b/chrome/app/chrome_main_delegate.cc
@@ -30,6 +30,7 @@
 #include "chrome/renderer/chrome_content_renderer_client.h"
 #include "chrome/utility/chrome_content_utility_client.h"
 #include "content/public/common/content_client.h"
+#include "content/public/common/content_debug_logging.h"
 #include "content/public/common/content_paths.h"
 #include "content/public/common/content_switches.h"
 #include "ui/base/ui_base_switches.h"
@@ -369,6 +370,47 @@ struct MainFunction {
   int (*function)(const content::MainFunctionParams&);
 };
 
+// Limit message count and size to prevent rogue processes from
+// bloating memory use.
+const size_t kMaxBugMessages = 20;
+const size_t kMaxMessageSize = 64;
+
+// Locks g_messages.
+static base::LazyInstance<base::Lock>::Leaky
+    g_messages_lock = LAZY_INSTANCE_INITIALIZER;
+
+// Map bug ids to messages for that bug.
+// TODO(shess): Would multimap<> maintain the items in order added?
+base::LazyInstance<std::map<int, std::vector<std::string> > >
+    g_messages = LAZY_INSTANCE_INITIALIZER;
+
+void RecordMsg(int bug_id, const std::string& msg) {
+  // Only record information about specific bugs to prevent rogue
+  // processes from bloating memory usage.
+  CHECK(bug_id == 97285 || bug_id == 141055);
+
+  // Make sure legitimate clients know that things are getting too big
+  // to handle.
+  DCHECK_LE(msg.size(), kMaxMessageSize);
+
+  base::AutoLock pin(g_messages_lock.Get());
+  std::vector<std::string>& bug_messages = g_messages.Get()[bug_id];
+  bug_messages.push_back(msg.substr(0, kMaxMessageSize));
+
+  // Should only remove a single item.
+  while (bug_messages.size() > kMaxBugMessages)
+    bug_messages.erase(bug_messages.begin());
+}
+
+bool GetMessages(int bug_id, std::vector<std::string>* msgs) {
+  CHECK(bug_id == 97285 || bug_id == 141055);
+
+  base::AutoLock pin(g_messages_lock.Get());
+  std::vector<std::string>& bug_messages = g_messages.Get()[bug_id];
+  msgs->assign(bug_messages.begin(), bug_messages.end());

[Bernhard Bauer, 2012/09/05 15:04:55]

Could you just write `*msgs = g_messages.Get()[bug_id];`?

[Scott Hess - ex-Googler, 2012/09/05 17:17:05]

Done.  Sometimes it's harder to see the things which don't look right for C.

+  return !msgs->empty();
+}
+
 }  // namespace
 
 ChromeMainDelegate::ChromeMainDelegate() {
@@ -525,6 +567,10 @@ void ChromeMainDelegate::PreSandboxStartup() {
   std::string process_type =
       command_line.GetSwitchValueASCII(switches::kProcessType);
 
+  // TODO(shess): Could this be registered earlier?
+  if (process_type.empty())
+    content::debug::RegisterMessageHandlers(RecordMsg, GetMessages);
+
   chrome::RegisterPathProvider();
 
 #if defined(OS_MACOSX)