Matt Watson wrote:
void fatalSigHandler(int sig, siginfo_t* info, void* context)
{
// We are very limited in what we are allowed to do in a signal
handler. // Memory should not be allocated, and most libc
functions should not be used.
static char sig_message[] = "Aborting: Fatal signal occurred!\n";
write(1, sig_message, sizeof(sig_message));
exit(1);
}
Never call exit() from a signal handler. You want _Exit() instead.
exit() will call atexit() handlers which will are likely not
signal-safe. And you probably want to use fd 2 (stderr), instead of
fd 1 in the write() call.
Good suggestions. That's especially important when using dlopen or
NSLinkModule on libraries. They could cause further signals or even
signal deadlocks when they get unloaded.
That said: if you're not going to add any more info in your signal
handler, or do any cleanup like unlink() files, it may just be best
to let it crash and generate a crash log.
I assumed that he'd replace the handler with something else.
One of the handlers I have for a project calls execv() to restart the
daemon in case of a crash. That is after writing errors to a log and
closing open file handles/resetting signal masks (as they are both
inherited by the new process), and doing some other general cleanup
of the daemon's lock/state files.
-Kevin-
Thanks everyone!!!!
I hope no one minds if I take this one step further. Is there actually
a way to have it return to the offending code with an exception
triggered? For example, would the following snippet work...
#define kMySigError -9999
void fatalSigHandler(int sig, siginfo_t* info, void* context)
{
short pErr = kMySigError;
throw(pErr);
_Exit(1); //Not that this will ever be reached
}
main(){
Ptr ptrFoo = nil;
char barrrr;
installSignalHandler(SIGSEGV, &fatalSigHandler);
installSignalHandler(SIGBUS, &fatalSigHandler);
try{
barrrr = (*ptrFoo);
}catch(short err){
printf("Error %x", err);
}
....continue
return(noErr);
}
Rick
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