Accept non-fatal resource exceptions without generating crash reports

handler/mac/crash_report_exception_handler.cc

 // 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,
@@ skipping 10 matching lines @@
 #include "base/logging.h"
 #include "base/mac/mach_logging.h"
 #include "base/strings/stringprintf.h"
 #include "client/settings.h"
 #include "minidump/minidump_file_writer.h"
 #include "snapshot/mac/crashpad_info_client_options.h"
 #include "snapshot/mac/process_snapshot_mac.h"
 #include "util/file/file_writer.h"
 #include "util/mach/exc_client_variants.h"
 #include "util/mach/exception_behaviors.h"
+#include "util/mach/exception_types.h"
 #include "util/mach/mach_extensions.h"
 #include "util/mach/mach_message.h"
 #include "util/mach/scoped_task_suspend.h"
 #include "util/mach/symbolic_constants_mach.h"
 #include "util/misc/tri_state.h"
 #include "util/misc/uuid.h"
 
 namespace crashpad {
 
 CrashReportExceptionHandler::CrashReportExceptionHandler(
@@ skipping 53 matching lines @@
     return KERN_FAILURE;
   }
 
   // Check for suspicious message sources. A suspicious exception message comes
   // from a source other than the kernel or the process that the exception
   // purportedly occurred in.
   //
   // TODO(mark): Consider exceptions outside of the range (0, 32) from the
   // kernel to be suspicious, and exceptions other than kMachExceptionSimulated
   // from the process itself to be suspicious.
+  const pid_t pid = process_snapshot.ProcessID();
   pid_t audit_pid = AuditPIDFromMachMessageTrailer(trailer);
   if (audit_pid != -1 && audit_pid != 0) {
-    pid_t exception_pid = process_snapshot.ProcessID();
-    if (exception_pid != audit_pid) {
-      LOG(WARNING) << "exception for pid " << exception_pid << " sent by pid "
+    if (audit_pid != pid) {
+      LOG(WARNING) << "exception for pid " << pid << " sent by pid "
                    << audit_pid;
     }
   }
 
+  if (IsExceptionNonfatalResource(exception, code[0], pid)) {
+    // Swallow non-fatal resource exceptions.
+    //
+    // Normally, all EXC_RESOURCE exceptions go to the host-level EXC_RESOURCE
+    // handler, com.apple.ReportCrash.root, which invokes spindump to handle
+    // them. These non-fatal exceptions are never user-visible and are not
+    // currently of interest to Crashpad. Returning success here gets the
+    // process going again quickly, without generating a crash report.
+    //
+    // Alternatively, this could return KERN_FAILURE to let the exception go to
+    // the host-level handler, but there doesn’t seem to be much value in doing
+    // so.
+    ExcServerCopyState(
+        behavior, old_state, old_state_count, new_state, new_state_count);
+    return ExcServerSuccessfulReturnValue(behavior, false);
+  }
+
   CrashpadInfoClientOptions client_options;
   process_snapshot.GetCrashpadOptions(&client_options);
 
   if (client_options.crashpad_handler_behavior != TriState::kDisabled) {
     if (!process_snapshot.InitializeException(behavior,
                                               thread,
                                               exception,
                                               code,
                                               code_count,
                                               *flavor,
@@ skipping 111 matching lines @@
 
   if (!forwarded) {
     ExcServerCopyState(
         behavior, old_state, old_state_count, new_state, new_state_count);
   }
 
   return ExcServerSuccessfulReturnValue(behavior, false);
 }
 
 }  // namespace crashpad