/* * signal.c * Implement signal-based exception handling * * Copyright (c) 1996, 1997, 1998, 1999 *	Transvirtual Technologies, Inc.  All rights reserved. * * See the file "license.terms" for information on usage and redistribution  * of this file.  */#include "config.h"#include "debug.h"#include "config-std.h"#include "config-signal.h"#include "config-mem.h"#include "config-setjmp.h"#include "jthread.h"#include "jsignal.h"#include "md.h"#include "gc.h"#if defined(INTERPRETER)#define	DEFINEFRAME()		/* Does nothing */#define	EXCEPTIONPROTO		int sig#define	EXCEPTIONFRAME(f, c)	/* Does nothing */#define	EXCEPTIONFRAMEPTR	0#elif defined(TRANSLATOR)#define	DEFINEFRAME()		exceptionFrame frame#define	EXCEPTIONFRAMEPTR	&frame#endif /* TRANSLATOR */static void nullException(EXCEPTIONPROTO);static void floatingException(EXCEPTIONPROTO);static exchandler_t nullHandler;static exchandler_t floatingHandler;/* * Setup the internal exceptions. */voidjthread_initexceptions(exchandler_t _nullHandler,		       exchandler_t _floatingHandler){	nullHandler = _nullHandler;	floatingHandler = _floatingHandler;	if (DBGEXPR(EXCEPTION, false, true)) {		/* Catch signals we need to convert to exceptions */#if defined(SIGSEGV)		registerSyncSignalHandler(SIGSEGV, nullException);#endif#if defined(SIGBUS)		registerSyncSignalHandler(SIGBUS, nullException);#endif#if defined(SIGFPE)		registerSyncSignalHandler(SIGFPE, floatingException);#endif#if defined(SIGPIPE)		ignoreSignal(SIGPIPE);#endif	}}/* * Null exception - catches bad memory accesses. */static voidnullException(EXCEPTIONPROTO){	DEFINEFRAME();#if defined(__FreeBSD__) && !defined(INTERPRETER)	if ((uintp) ctx->sc_err > gc_heap_base) {		dprintf("accessing free page %p (above %p)\n",			(void*) ctx->sc_err, (void *) gc_heap_base);		abort();	}#endif	/* Restore the signal handler if necessary */	restoreSyncSignalHandler(sig, nullException);	/* Clean up the synchronous signal state (just unblock this signal) */	unblockSignal(sig);	EXCEPTIONFRAME(frame, ctx);	nullHandler(EXCEPTIONFRAMEPTR);}/* * Division by zero. */static voidfloatingException(EXCEPTIONPROTO){	DEFINEFRAME();	/* Restore the signal handler if necessary */	restoreSyncSignalHandler(sig, floatingException);	/* Clean up the synchronous signal state (just unblock this signal) */	unblockSignal(sig);	EXCEPTIONFRAME(frame, ctx);	floatingHandler(EXCEPTIONFRAMEPTR);}/* ----------------------------------------------- * OS signal handling code.  See FAQ/FAQ.jsignal for information. * ----------------------------------------------- */static voidregisterSignalHandler(int sig, void* handler, int isAsync){#if defined(HAVE_SIGACTION)	struct sigaction newact;	newact.sa_handler = (SIG_T)handler;	sigemptyset(&newact.sa_mask);	/*	 * Define sa_mask to include the signals to block when	 * running handler.	 */	if (isAsync) {		sigaddset(&newact.sa_mask, SIGIO);		sigaddset(&newact.sa_mask, SIGALRM);		sigaddset(&newact.sa_mask, SIGCHLD);#if defined(SIGVTALRM)		sigaddset(&newact.sa_mask, SIGVTALRM);#endif	}	newact.sa_flags = 0;#if defined(SA_SIGINFO)	newact.sa_flags |= SA_SIGINFO;#endif#if defined(SA_RESTART)	newact.sa_flags |= SA_RESTART;#endif	sigaction(sig, &newact, NULL);#elif defined(HAVE_SIGNAL)#warning The default signal() semantics may not be sufficient for Kaffe.	signal(sig, (SIG_T)handler);#else#error No signal handler support.  Jthreads requires signal support.	#endif /* HAVE_SIGACTION */}/* * Register a handler for an asynchronous signal. */voidregisterAsyncSignalHandler(int sig, void* handler){	int validSig = 		(sig == SIGALRM)#if defined(SIGVTALRM)		|| (sig == SIGVTALRM) #endif		|| (sig == SIGIO)		|| (sig == SIGUSR1)		|| (sig == SIGCHLD);	/* Make sure its really an asynchronous signal being registered. */	assert(handler != NULL);	assert(validSig);  /* Can't have the #ifdef in a macro arg. */	/*	 * Register an asynchronous signal handler that will block all	 * other asynchronous signals while the handler is running.	 */	registerSignalHandler(sig, handler, true);}/* * Register a signal handler for a synchronous signal. */voidregisterSyncSignalHandler(int sig, void* handler){	int validSig = 0#if defined(SIGFPE)	       		|| (sig == SIGFPE)#endif#if defined(SIGSEGV)		|| (sig == SIGSEGV)#endif#if defined(SIGBUS)		|| (sig == SIGBUS)#endif		;		assert(handler != NULL);	assert(validSig);		/* Register a synchronous signal handler */	registerSignalHandler(sig, handler, false);}/* * Restore an asynchronous signal handler.   * Only necesary on some platforms which don't provide SIGACTION */voidrestoreAsyncSignalHandler(int sig, void* handler){#if !defined(HAVE_SIGACTION)	/* XXX need a configure-time test for this. */	registerAsyncSignalHandler(sig, handler);#endif}/* * Restore a synchronous signal handler.   * Only necesary on some platforms. */voidrestoreSyncSignalHandler(int sig, void* handler){#if !defined(HAVE_SIGACTION)	/* XXX need a configure-time test for this. */	registerSyncSignalHandler(sig, handler);#endif}/* * Register a handler for a terminal (i.e., process-killing) signal. * These handlers must exit(). */voidregisterTerminalSignal(int sig, void* handler){	assert((sig == SIGINT) || (sig == SIGTERM));	registerSignalHandler(sig, handler, true);}/* * Clear the given signal (i.e., restore the default behavior of the signal) */voidclearSignal(int sig){	registerSignalHandler(sig, SIG_DFL, false);}/* * Ignore the given signal. */voidignoreSignal(int sig){	registerSignalHandler(sig, SIG_IGN, false);}/* * Unblock the given signal. */voidunblockSignal(int sig){	sigset_t nsig;	sigemptyset(&nsig);	sigaddset(&nsig, sig);	sigprocmask(SIG_UNBLOCK, &nsig, 0);}/* * Unblock all of the async signals.  (These are the * signals specified in the sa_mask in registerAsynchSignalHandler().) */void unblockAsyncSignals(void){	sigset_t nsig;	sigemptyset(&nsig);	sigaddset(&nsig, SIGIO);	sigaddset(&nsig, SIGALRM);	sigaddset(&nsig, SIGCHLD);#if defined(SIGVTALRM)	sigaddset(&nsig, SIGVTALRM);#endif	sigprocmask(SIG_UNBLOCK, &nsig, 0);	}/* * Block all of the async signals.  (These are the * signals specified in the sa_mask in registerAsynchSignalHandler().) */void blockAsyncSignals(void){	sigset_t nsig;	sigemptyset(&nsig);	sigaddset(&nsig, SIGIO);	sigaddset(&nsig, SIGALRM);	sigaddset(&nsig, SIGCHLD);#if defined(SIGVTALRM)	sigaddset(&nsig, SIGVTALRM);#endif	sigprocmask(SIG_BLOCK, &nsig, 0);	}