ObjFW  Diff

/*
 * Copyright (c) 2008-2021 Jonathan Schleifer <js@nil.im>
 *
 * All rights reserved.
 *
 * This file is part of ObjFW. It may be distributed under the terms of the
 * Q Public License 1.0, which can be found in the file LICENSE.QPL included in
 * the packaging of this file.
 *

# define CALL_PERSONALITY(func) func(state, ex, ctx)
#endif

#define GNUCOBJC_EXCEPTION_CLASS UINT64_C(0x474E55434F424A43) /* GNUCOBJC */
#define GNUCCXX0_EXCEPTION_CLASS UINT64_C(0x474E5543432B2B00) /* GNUCC++\0 */
#define CLNGCXX0_EXCEPTION_CLASS UINT64_C(0x434C4E47432B2B00) /* CLNGC++\0 */

#define NUM_EMERGENCY_EXCEPTIONS 4


#define _UA_SEARCH_PHASE  0x01
#define _UA_CLEANUP_PHASE 0x02
#define _UA_HANDLER_FRAME 0x04
#define _UA_FORCE_UNWIND  0x08



#define DW_EH_PE_absptr	  0x00

#define DW_EH_PE_uleb128  0x01
#define DW_EH_PE_udata2	  0x02
#define DW_EH_PE_udata4	  0x03
#define DW_EH_PE_udata8	  0x04

#define DW_EH_PE_signed	  0x08
#define DW_EH_PE_sleb128  (DW_EH_PE_signed | DW_EH_PE_uleb128)
#define DW_EH_PE_sdata2	  (DW_EH_PE_signed | DW_EH_PE_udata2)
#define DW_EH_PE_sdata4	  (DW_EH_PE_signed | DW_EH_PE_udata4)
#define DW_EH_PE_sdata8	  (DW_EH_PE_signed | DW_EH_PE_udata8)

#define DW_EH_PE_pcrel	  0x10
#define DW_EH_PE_textrel  0x20
#define DW_EH_PE_datarel  0x30
#define DW_EH_PE_funcrel  0x40
#define DW_EH_PE_aligned  0x50

#define DW_EH_PE_indirect 0x80

#define DW_EH_PE_omit	  0xFF



#define CLEANUP_FOUND	  0x01
#define HANDLER_FOUND	  0x02


struct _Unwind_Context;

typedef enum {
	_URC_OK			= 0,
	_URC_FATAL_PHASE1_ERROR	= 3,
	_URC_END_OF_STACK	= 5,

	id object;
#ifndef HAVE_ARM_EHABI_EXCEPTIONS
	uintptr_t landingpad;
	intptr_t filter;
#endif
};

struct lsda {
	uintptr_t regionStart, landingpadsStart;
	uint8_t typesTableEnc;
	const uint8_t *typesTable;
	uintptr_t typesTableBase;
	uint8_t callsitesEnc;
	const uint8_t *callsites, *actionTable;
};

#ifdef HAVE_SEH_EXCEPTIONS
extern EXCEPTION_DISPOSITION _GCC_specific_handler(PEXCEPTION_RECORD, void *,
    PCONTEXT, PDISPATCHER_CONTEXT, _Unwind_Reason_Code (*)(int, int, uint64_t,
    struct _Unwind_Exception *, struct _Unwind_Context *));
#endif

static objc_uncaught_exception_handler_t uncaughtExceptionHandler;
static struct objc_exception emergencyExceptions[NUM_EMERGENCY_EXCEPTIONS];
#ifdef OF_HAVE_THREADS
static OFSpinlock emergencyExceptionsSpinlock;

OF_CONSTRUCTOR()
{
	if (OFSpinlockNew(&emergencyExceptionsSpinlock) != 0)
		OBJC_ERROR("Cannot create spinlock!");
}
#endif

static uint64_t
readULEB128(const uint8_t **ptr)
{
	uint64_t value = 0;

		value = *(uintptr_t *)(uintptr_t)value;

	return value;
}
#endif

static void
readLSDA(struct _Unwind_Context *ctx, const uint8_t *ptr, struct lsda *LSDA)
{
	uint8_t landingpadsStartEnc;
	uintptr_t callsitesSize;

	LSDA->regionStart = _Unwind_GetRegionStart(ctx);
	LSDA->landingpadsStart = LSDA->regionStart;
	LSDA->typesTable = NULL;

	callsitesSize = (uintptr_t)readULEB128(&ptr);
	LSDA->callsites = ptr;

	LSDA->actionTable = LSDA->callsites + callsitesSize;
}

static bool
findCallsite(struct _Unwind_Context *ctx, struct lsda *LSDA,
    uintptr_t *landingpad, const uint8_t **actionRecords)
{
	uintptr_t IP = _Unwind_GetIP(ctx);
	const uint8_t *ptr = LSDA->callsites;

	*landingpad = 0;
	*actionRecords = NULL;

		if (iter == class)
			return true;

	return false;
}

static uint8_t
findActionRecord(const uint8_t *actionRecords, struct lsda *LSDA, int actions,
    bool foreign, struct objc_exception *e, intptr_t *filterPtr)
{
	const uint8_t *ptr;
	intptr_t filter, displacement;

	do {
		ptr = actionRecords;

	}

	_Unwind_SetGR(ctx, 12, (uintptr_t)ex);
#endif
	struct objc_exception *e = (struct objc_exception *)ex;
	bool foreign = (exClass != GNUCOBJC_EXCEPTION_CLASS);
	const uint8_t *LSDAAddr, *actionRecords;
	struct lsda LSDA;
	uintptr_t landingpad = 0;
	uint8_t found = 0;
	intptr_t filter = 0;

	if (foreign) {
		switch (exClass) {
#ifdef CXX_PERSONALITY

static void
emergencyExceptionCleanup(_Unwind_Reason_Code reason,
    struct _Unwind_Exception *ex)
{
#ifdef OF_HAVE_THREADS
	if (OFSpinlockLock(&emergencyExceptionsSpinlock) != 0)
		OBJC_ERROR("Cannot lock spinlock!");
#endif

	ex->class = 0;

#ifdef OF_HAVE_THREADS
	if (OFSpinlockUnlock(&emergencyExceptionsSpinlock) != 0)
		OBJC_ERROR("Cannot unlock spinlock!");
#endif
}

void
objc_exception_throw(id object)
{
	struct objc_exception *e = calloc(1, sizeof(*e));
	bool emergency = false;

	if (e == NULL) {
#ifdef OF_HAVE_THREADS
		if (OFSpinlockLock(&emergencyExceptionsSpinlock) != 0)
			OBJC_ERROR("Cannot lock spinlock!");
#endif

		for (uint_fast8_t i = 0; i < NUM_EMERGENCY_EXCEPTIONS; i++) {
			if (emergencyExceptions[i].exception.class == 0) {
				e = &emergencyExceptions[i];
				e->exception.class = GNUCOBJC_EXCEPTION_CLASS;
				emergency = true;

				break;
			}
		}

#ifdef OF_HAVE_THREADS
		if (OFSpinlockUnlock(&emergencyExceptionsSpinlock) != 0)
			OBJC_ERROR("Cannot lock spinlock!");
#endif
	}

	if (e == NULL)
		OBJC_ERROR("Not enough memory to allocate exception!");

	e->exception.class = GNUCOBJC_EXCEPTION_CLASS;
	e->exception.cleanup = (emergency
	    ? emergencyExceptionCleanup : cleanup);
	e->object = object;

	_Unwind_RaiseException(&e->exception);

	if (uncaughtExceptionHandler != NULL)
		uncaughtExceptionHandler(object);

	OBJC_ERROR("_Unwind_RaiseException() returned!");
}

objc_uncaught_exception_handler_t
objc_setUncaughtExceptionHandler(objc_uncaught_exception_handler_t handler)
{
	objc_uncaught_exception_handler_t old = uncaughtExceptionHandler;
	uncaughtExceptionHandler = handler;

	return old;
}

#ifdef HAVE_SEH_EXCEPTIONS
typedef EXCEPTION_DISPOSITION (*seh_personality_fn)(PEXCEPTION_RECORD, void *,