I'm trying to build my own signal and uncaught exception handler for iOS. To do this i use these two functions :
NSSetUncaughtExceptionHandler(/*handler*/);
and
signal(/*signal const*/, /*signal handler*/);
My problem is that i can't make it work with EXC_BAD_ACCESS signal. Is there some signal constant (like SIGABRT, SIGBUS) to catch the EXC_BAD_ACCESS? If no, how can i handle it? Some crash analytics tools (lika PLCrashReporter, Crashlytics etc.) can trace it...
EXC_BAD_ACCESS
doesn't generate an exception so you first function doesn't work with the case. It generates a signal SIGSEGV
or SIGBUS
.
Please refer to Handling unhandled exceptions and signals by Cocoa with Love.
Update
I just checked the source code of LLDB. It might be TARGET_EXC_BAD_ACCESS
= 0x91.
In RNBRemote.h:
/* We translate the /usr/include/mach/exception_types.h exception types
(e.g. EXC_BAD_ACCESS) to the fake BSD signal numbers that gdb uses
in include/gdb/signals.h (e.g. TARGET_EXC_BAD_ACCESS). These hard
coded values for TARGET_EXC_BAD_ACCESS et al must match the gdb
values in its include/gdb/signals.h. */
#define TARGET_EXC_BAD_ACCESS 0x91
#define TARGET_EXC_BAD_INSTRUCTION 0x92
#define TARGET_EXC_ARITHMETIC 0x93
#define TARGET_EXC_EMULATION 0x94
#define TARGET_EXC_SOFTWARE 0x95
#define TARGET_EXC_BREAKPOINT 0x96
and in RNBRemote.cpp:
// Translate any mach exceptions to gdb versions, unless they are
// common exceptions like a breakpoint or a soft signal.
switch (tid_stop_info.details.exception.type)
{
default: signum = 0; break;
case EXC_BREAKPOINT: signum = SIGTRAP; break;
case EXC_BAD_ACCESS: signum = TARGET_EXC_BAD_ACCESS; break;
case EXC_BAD_INSTRUCTION: signum = TARGET_EXC_BAD_INSTRUCTION; break;
case EXC_ARITHMETIC: signum = TARGET_EXC_ARITHMETIC; break;
case EXC_EMULATION: signum = TARGET_EXC_EMULATION; break;
case EXC_SOFTWARE:
if (tid_stop_info.details.exception.data_count == 2 &&
tid_stop_info.details.exception.data[0] == EXC_SOFT_SIGNAL)
signum = tid_stop_info.details.exception.data[1];
else
signum = TARGET_EXC_SOFTWARE;
break;
}