Ensure the OSX crash catcher does not trigger on SIGABRT when disabled.

base/mac/os_crash_dumps.cc

 // Copyright (c) 2010 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.
 
 #include "base/mac/os_crash_dumps.h"
 
 #include <signal.h>
 #include <unistd.h>
 
 #include "base/basictypes.h"
@@ skipping 14 matching lines @@
 }  // namespace
 
 void DisableOSCrashDumps() {
   // These are the POSIX signals corresponding to the Mach exceptions that
   // Apple Crash Reporter handles.  See ux_exception() in xnu's
   // bsd/uxkern/ux_exception.c and machine_exception() in xnu's
   // bsd/dev/*/unix_signal.c.
   const int signals_to_intercept[] = {
     SIGILL,   // EXC_BAD_INSTRUCTION
     SIGTRAP,  // EXC_BREAKPOINT
+    SIGABRT,  // EXC_CRASH

[Mark Seaborn, 2014/06/19 18:28:14]

FWIW, the comment is misleading.

See
http://lackingrhoticity.blogspot.com/2013/08/handling-crashes-on-mac-os-x.html

Any hardware fault will trigger a Mach exception like EXC_BAD_INSTRUCTION,
EXC_ARITHMETIC, EXC_BAD_ACCESS, etc.

If the Mach exception handler passes the exception on, it gets converted to a
POSIX signal: SIGFPE, SIGBUS, etc.

If a POSIX signal is unhandled, it triggers the EXC_CRASH Mach exception.

So any fatal POSIX signal will be converted to EXC_CRASH.  SIGABRT is never
generated by a hardware fault, only by syscalls like kill() and raise().

So, can you write something like:
  const int signals_to_intercept[] = {
    // Hardware faults
    SIGILL,   // EXC_BAD_INSTRUCTION
    SIGTRAP,  // EXC_BREAKPOINT
    SIGFPE,   // EXC_ARITHMETIC
    SIGBUS,   // EXC_BAD_ACCESS
    SIGSEGV   // EXC_BAD_ACCESS
    // Not a hardware fault
    SIGABRT,
  };

[Nick Bray (chromium), 2014/06/19 20:49:55]

Done.

     SIGFPE,   // EXC_ARITHMETIC
     SIGBUS,   // EXC_BAD_ACCESS
     SIGSEGV   // EXC_BAD_ACCESS
   };
 
   // For all these signals, just wire things up so we exit immediately.
   for (size_t i = 0; i < arraysize(signals_to_intercept); ++i) {
     struct sigaction act = {};
     act.sa_handler = ExitSignalHandler;
 
     // It is better to allow the signal handler to run on the stack
     // registered with sigaltstack(), if one is present.
     act.sa_flags = SA_ONSTACK;
 
     if (sigemptyset(&act.sa_mask) != 0)
       DPLOG(FATAL) << "sigemptyset() failed";
     if (sigaction(signals_to_intercept[i], &act, NULL) != 0)
       DPLOG(FATAL) << "sigaction() failed";
   }
 }
 
 }  // namespace mac
 }  // namespace base