Handle EXC_RESOURCE and EXC_GUARD exceptions properly

client/crashpad_client_mac.cc

 // Copyright 2014 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 170 matching lines @@
   DCHECK_NE(exception_port_, kMachPortNull);
 
   // Set the exception handler for EXC_CRASH, EXC_RESOURCE, and EXC_GUARD.
   //
   // EXC_CRASH is how most crashes are received. Most other exception types such
   // as EXC_BAD_ACCESS are delivered to a host-level exception handler in the
   // kernel where they are converted to POSIX signals. See 10.9.5
   // xnu-2422.115.4/bsd/uxkern/ux_exception.c catch_mach_exception_raise(). If a
   // core-generating signal (triggered through this hardware mechanism or a
   // software mechanism such as abort() sending SIGABRT) is unhandled and the
-  // process exits, the exception becomes EXC_CRASH. See 10.9.5
+  // process exits, or if the process is killed with SIGKILL for code-signing
+  // reasons, an EXC_CRASH exception will be sent. See 10.9.5
   // xnu-2422.115.4/bsd/kern/kern_exit.c proc_prepareexit().
   //
   // EXC_RESOURCE and EXC_GUARD do not become signals or EXC_CRASH exceptions.
   // The host-level exception handler in the kernel does not receive these
   // exception types, and even if it did, it would not map them to signals.
   // Instead, the first Mach service loaded by the root (process ID 1) launchd
   // with a boolean “ExceptionServer” property in its job dictionary (regardless
   // of its value) or with any subdictionary property will become the host-level
   // exception handler for EXC_CRASH, EXC_RESOURCE, and EXC_GUARD. See 10.9.5
   // launchd-842.92.1/src/core.c job_setup_exception_port(). Normally, this job
@@ skipping 15 matching lines @@
           exception_port_,
           EXCEPTION_STATE_IDENTITY | MACH_EXCEPTION_CODES,
           MACHINE_THREAD_STATE)) {
     return false;
   }
 
   return true;
 }
 
 }  // namespace crashpad