/* * Copyright (c) 2008-2024 Jonathan Schleifer <js@nil.im> * * All rights reserved. * * This program is free software: you can redistribute it and/or modify it * under the terms of the GNU Lesser General Public License version 3.0 only, * as published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License * version 3.0 for more details. * * You should have received a copy of the GNU Lesser General Public License * version 3.0 along with this program. If not, see * <https://www.gnu.org/licenses/>. */ #include "config.h" #define OBJC_NO_PERSONALITY_DECLARATION #include <stdio.h> #include <stdlib.h> #include <string.h> #import "ObjFWRT.h" #import "private.h" #import "macros.h" #ifdef OF_HAVE_THREADS # import "OFPlainMutex.h" #endif #ifdef __SEH__ # include <windows.h> #endif #if defined(__SEH__) # define PERSONALITY gnu_objc_personality #elif defined(__USING_SJLJ_EXCEPTIONS__) # define PERSONALITY __gnu_objc_personality_sj0 # define CXX_PERSONALITY_STR "__gxx_personality_sj0" # define _Unwind_RaiseException _Unwind_SjLj_RaiseException # define __builtin_eh_return_data_regno(i) (i) #else # define PERSONALITY __gnu_objc_personality_v0 # define CXX_PERSONALITY_STR "__gxx_personality_v0" #endif #if defined(OF_ARM) && !defined(__ARM_DWARF_EH__) # define HAVE_ARM_EHABI_EXCEPTIONS #endif #ifndef HAVE_ARM_EHABI_EXCEPTIONS # define PERSONALITY_FUNC(func) \ _Unwind_Reason_Code \ func(int version, int actions, uint64_t exClass, \ struct _Unwind_Exception *ex, struct _Unwind_Context *ctx) # define CALL_PERSONALITY(func) func(version, actions, exClass, ex, ctx) #else # define PERSONALITY_FUNC(func) \ _Unwind_Reason_Code \ func(uint32_t state, struct _Unwind_Exception *ex, \ struct _Unwind_Context *ctx) # 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 numEmergencyExceptions 4 enum { _UA_SEARCH_PHASE = 0x01, _UA_CLEANUP_PHASE = 0x02, _UA_HANDLER_FRAME = 0x04, _UA_FORCE_UNWIND = 0x08 }; enum { DW_EH_PE_absptr = 0x00, DW_EH_PE_uleb128 = 0x01, DW_EH_PE_udata2 = 0x02, DW_EH_PE_udata4 = 0x03, DW_EH_PE_udata8 = 0x04, DW_EH_PE_signed = 0x08, DW_EH_PE_sleb128 = (DW_EH_PE_signed | DW_EH_PE_uleb128), DW_EH_PE_sdata2 = (DW_EH_PE_signed | DW_EH_PE_udata2), DW_EH_PE_sdata4 = (DW_EH_PE_signed | DW_EH_PE_udata4), DW_EH_PE_sdata8 = (DW_EH_PE_signed | DW_EH_PE_udata8), DW_EH_PE_pcrel = 0x10, DW_EH_PE_textrel = 0x20, DW_EH_PE_datarel = 0x30, DW_EH_PE_funcrel = 0x40, DW_EH_PE_aligned = 0x50, DW_EH_PE_indirect = 0x80, DW_EH_PE_omit = 0xFF }; enum { CLEANUP_FOUND = 0x01, HANDLER_FOUND = 0x02 }; struct _Unwind_Context; typedef enum { _URC_OK = 0, _URC_FATAL_PHASE1_ERROR = 3, _URC_END_OF_STACK = 5, _URC_HANDLER_FOUND = 6, _URC_INSTALL_CONTEXT = 7, _URC_CONTINUE_UNWIND = 8, _URC_FAILURE = 9 } _Unwind_Reason_Code; struct objc_exception { struct _Unwind_Exception { uint64_t class; void (*cleanup)( _Unwind_Reason_Code, struct _Unwind_Exception *); #ifndef HAVE_ARM_EHABI_EXCEPTIONS # ifndef __SEH__ /* * The Itanium Exception ABI says to have those and never touch * them. */ uint64_t private1, private2; # else uint64_t private[6]; # endif #else /* From "Exception Handling ABI for the ARM(R) Architecture" */ struct { uint32_t reserved1, reserved2, reserved3, reserved4; uint32_t reserved; } unwinderCache; struct { uint32_t sp; uint32_t bitPattern[5]; } barrierCache; struct { uint32_t bitPattern[4]; } cleanupCache; struct { uint32_t fnstart; uint32_t *ehtp; uint32_t additional; uint32_t reserved1; } PRCache; long long int : 0; #endif } exception; 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; }; extern _Unwind_Reason_Code _Unwind_RaiseException(struct _Unwind_Exception *); extern void _Unwind_DeleteException(struct _Unwind_Exception *); extern void *_Unwind_GetLanguageSpecificData(struct _Unwind_Context *); extern uintptr_t _Unwind_GetRegionStart(struct _Unwind_Context *); #ifdef HAVE__UNWIND_GETDATARELBASE extern uintptr_t _Unwind_GetDataRelBase(struct _Unwind_Context *); #endif #ifdef HAVE__UNWIND_GETTEXTRELBASE extern uintptr_t _Unwind_GetTextRelBase(struct _Unwind_Context *); #endif #ifndef HAVE_ARM_EHABI_EXCEPTIONS # define CONTINUE_UNWIND return _URC_CONTINUE_UNWIND extern uintptr_t _Unwind_GetIP(struct _Unwind_Context *); extern uintptr_t _Unwind_GetGR(struct _Unwind_Context *, int); extern void _Unwind_SetIP(struct _Unwind_Context *, uintptr_t); extern void _Unwind_SetGR(struct _Unwind_Context *, int, uintptr_t); #else extern _Unwind_Reason_Code __gnu_unwind_frame(struct _Unwind_Exception *, struct _Unwind_Context *); extern int _Unwind_VRS_Get(struct _Unwind_Context *, int, uint32_t, int, void *); extern int _Unwind_VRS_Set(struct _Unwind_Context *, int, uint32_t, int, void *); # define CONTINUE_UNWIND \ { \ if (__gnu_unwind_frame(ex, ctx) != _URC_OK) \ return _URC_FAILURE; \ \ return _URC_CONTINUE_UNWIND; \ } static inline uintptr_t _Unwind_GetGR(struct _Unwind_Context *ctx, int regNo) { uintptr_t value; _Unwind_VRS_Get(ctx, 0, regNo, 0, &value); return value; } static inline uintptr_t _Unwind_GetIP(struct _Unwind_Context *ctx) { return _Unwind_GetGR(ctx, 15) & ~1; } static inline void _Unwind_SetGR(struct _Unwind_Context *ctx, int regNo, uintptr_t value) { _Unwind_VRS_Set(ctx, 0, regNo, 0, &value); } static inline void _Unwind_SetIP(struct _Unwind_Context *ctx, uintptr_t value) { uintptr_t thumb = _Unwind_GetGR(ctx, 15) & 1; _Unwind_SetGR(ctx, 15, (value | thumb)); } #endif #if defined(CXX_PERSONALITY_STR) && !defined(OF_AMIGAOS_M68K) static PERSONALITY_FUNC(cxx_personality) OF_WEAK_REF(CXX_PERSONALITY_STR); #endif #ifdef __SEH__ 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 uncaughtExceptionHandler; static struct objc_exception emergencyExceptions[numEmergencyExceptions]; #ifdef OF_HAVE_THREADS static OFSpinlock emergencyExceptionsSpinlock; OF_CONSTRUCTOR() { if (OFSpinlockNew(&emergencyExceptionsSpinlock) != 0) OBJC_ERROR("Failed to create spinlock!"); } #endif static uint64_t readULEB128(const uint8_t **ptr) { uint64_t value = 0; uint8_t shift = 0; do { value |= (**ptr & 0x7F) << shift; (*ptr)++; shift += 7; } while (*(*ptr - 1) & 0x80); return value; } static int64_t readSLEB128(const uint8_t **ptr) { const uint8_t *oldPtr = *ptr; uint8_t bits; int64_t value; value = readULEB128(ptr); bits = (*ptr - oldPtr) * 7; if (bits < 64 && value & (INT64_C(1) << (bits - 1))) value |= -(INT64_C(1) << bits); return value; } static uintptr_t getBase(struct _Unwind_Context *ctx, uint8_t enc) { if (enc == DW_EH_PE_omit) return 0; switch (enc & 0x70) { case DW_EH_PE_absptr: case DW_EH_PE_pcrel: case DW_EH_PE_aligned: return 0; case DW_EH_PE_funcrel: return _Unwind_GetRegionStart(ctx); #ifdef HAVE__UNWIND_GETDATARELBASE case DW_EH_PE_datarel: return _Unwind_GetDataRelBase(ctx); #else case DW_EH_PE_datarel: return _Unwind_GetGR(ctx, 1); #endif #ifdef HAVE__UNWIND_GETTEXTRELBASE case DW_EH_PE_textrel: return _Unwind_GetTextRelBase(ctx); #endif } OBJC_ERROR("Unknown encoding!"); } static size_t sizeForEncoding(uint8_t enc) { if (enc == DW_EH_PE_omit) return 0; switch (enc & 0x07) { case DW_EH_PE_absptr: return sizeof(void *); case DW_EH_PE_udata2: return 2; case DW_EH_PE_udata4: return 4; case DW_EH_PE_udata8: return 8; } OBJC_ERROR("Unknown encoding!"); } static uint64_t readValue(uint8_t enc, const uint8_t **ptr) { uint64_t value; if (enc == DW_EH_PE_aligned) { const uintptr_t *aligned = (const uintptr_t *) OFRoundUpToPowerOf2(sizeof(void *), (uintptr_t)*ptr); *ptr = (const uint8_t *)(aligned + 1); return *aligned; } #define READ(type) \ { \ type tmp; \ memcpy(&tmp, *ptr, sizeof(type)); \ value = tmp; \ *ptr += sizeForEncoding(enc); \ break; \ } switch (enc & 0x0F) { case DW_EH_PE_absptr: READ(uintptr_t) case DW_EH_PE_uleb128: value = readULEB128(ptr); break; case DW_EH_PE_udata2: READ(uint16_t) case DW_EH_PE_udata4: READ(uint32_t) case DW_EH_PE_udata8: READ(uint64_t) case DW_EH_PE_sleb128: value = readSLEB128(ptr); break; case DW_EH_PE_sdata2: READ(int16_t) case DW_EH_PE_sdata4: READ(int32_t) case DW_EH_PE_sdata8: READ(int64_t) default: OBJC_ERROR("Unknown encoding!"); } #undef READ return value; } #ifndef HAVE_ARM_EHABI_EXCEPTIONS static uint64_t resolveValue(uint64_t value, uint8_t enc, const uint8_t *start, uint64_t base) { if (value == 0 || enc == DW_EH_PE_aligned) return value; value += ((enc & 0x70) == DW_EH_PE_pcrel ? (uintptr_t)start : base); if (enc & DW_EH_PE_indirect) 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; if ((landingpadsStartEnc = *ptr++) != DW_EH_PE_omit) LSDA->landingpadsStart = (uintptr_t)readValue(landingpadsStartEnc, &ptr); if ((LSDA->typesTableEnc = *ptr++) != DW_EH_PE_omit) { uintptr_t tmp = (uintptr_t)readULEB128(&ptr); LSDA->typesTable = ptr + tmp; } LSDA->typesTableBase = getBase(ctx, LSDA->typesTableEnc); LSDA->callsitesEnc = *ptr++; 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; #ifndef __USING_SJLJ_EXCEPTIONS__ while (ptr < LSDA->actionTable) { uintptr_t callsiteStart, callsiteLength, callsiteLandingpad; uintptr_t callsiteAction; callsiteStart = LSDA->regionStart + (uintptr_t)readValue(LSDA->callsitesEnc, &ptr); callsiteLength = (uintptr_t)readValue(LSDA->callsitesEnc, &ptr); callsiteLandingpad = (uintptr_t)readValue(LSDA->callsitesEnc, &ptr); callsiteAction = (uintptr_t)readULEB128(&ptr); /* We can stop if we passed IP, as the table is sorted */ if (callsiteStart >= IP) break; if (callsiteStart + callsiteLength >= IP) { if (callsiteLandingpad != 0) *landingpad = LSDA->landingpadsStart + callsiteLandingpad; if (callsiteAction != 0) *actionRecords = LSDA->actionTable + callsiteAction - 1; return true; } } return false; #else uintptr_t callsiteLandingpad, callsiteAction; if ((intptr_t)IP < 1) return false; do { callsiteLandingpad = (uintptr_t)readULEB128(&ptr); callsiteAction = (uintptr_t)readULEB128(&ptr); } while (--IP > 1); *landingpad = callsiteLandingpad + 1; if (callsiteAction != 0) *actionRecords = LSDA->actionTable + callsiteAction - 1; return true; #endif } static bool classMatches(Class class, id object) { Class iter; if (class == Nil) return true; if (object == nil) return false; for (iter = object_getClass(object); iter != Nil; iter = class_getSuperclass(iter)) 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; filter = (intptr_t)readSLEB128(&ptr); /* * Get the next action record. Since readSLEB128() modifies ptr, * we first set the actionrecord to the current ptr and then * add the displacement. */ actionRecords = ptr; displacement = (intptr_t)readSLEB128(&ptr); actionRecords += displacement; if (filter > 0 && !(actions & _UA_FORCE_UNWIND) && !foreign) { Class class; const char *className; uintptr_t c; const uint8_t *tmp; #ifndef HAVE_ARM_EHABI_EXCEPTIONS uintptr_t i; i = filter * sizeForEncoding(LSDA->typesTableEnc); tmp = LSDA->typesTable - i; c = (uintptr_t)readValue(LSDA->typesTableEnc, &tmp); c = (uintptr_t)resolveValue(c, LSDA->typesTableEnc, LSDA->typesTable - i, LSDA->typesTableBase); #else tmp = LSDA->typesTable - (filter * 4); c = *(uintptr_t *)(void *)tmp; if (c != 0) { c += (uintptr_t)tmp; # if defined(OF_LINUX) || defined(OF_NETBSD) c = *(uintptr_t *)c; # endif } #endif className = (const char *)c; if (className != NULL && *className != '\0' && strcmp(className, "@id") != 0) class = objc_getRequiredClass(className); else class = Nil; if (classMatches(class, e->object)) { *filterPtr = filter; return HANDLER_FOUND; } } else if (filter == 0) return CLEANUP_FOUND; else if (filter < 0) OBJC_ERROR("Invalid filter!"); } while (displacement != 0); return 0; } #ifdef __SEH__ static #endif PERSONALITY_FUNC(PERSONALITY) { #ifdef HAVE_ARM_EHABI_EXCEPTIONS int version = 1; uint64_t exClass = ex->class; int actions; switch (state) { case 0: /* _US_VIRTUAL_UNWIND_FRAME */ actions = _UA_SEARCH_PHASE; break; case 1: /* _US_UNWIND_FRAME_STARTING */ actions = _UA_CLEANUP_PHASE; if ((ex->barrierCache.sp == _Unwind_GetGR(ctx, 13)) != 0) actions |= _UA_HANDLER_FRAME; break; case 2: /* _US_UNWIND_FRAME_RESUME */ CONTINUE_UNWIND; default: return _URC_FAILURE; } _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) { #if defined(CXX_PERSONALITY_STR) && !defined(OF_AMIGAOS_M68K) case GNUCCXX0_EXCEPTION_CLASS: case CLNGCXX0_EXCEPTION_CLASS: if (cxx_personality != NULL) return CALL_PERSONALITY(cxx_personality); break; #endif } /* * None matched or none available - we'll try to handle it * anyway, but will most likely fail. */ } if (version != 1 || ctx == NULL) return _URC_FATAL_PHASE1_ERROR; /* * We already cached everything we found in phase 1, so we only need * to install the context in phase 2. */ if (actions & _UA_HANDLER_FRAME && !foreign) { /* * For handlers, reg #0 must be the exception's object and reg * #1 the filter. */ _Unwind_SetGR(ctx, __builtin_eh_return_data_regno(0), (uintptr_t)e->object); #ifndef HAVE_ARM_EHABI_EXCEPTIONS _Unwind_SetGR(ctx, __builtin_eh_return_data_regno(1), e->filter); _Unwind_SetIP(ctx, e->landingpad); #else _Unwind_SetGR(ctx, __builtin_eh_return_data_regno(1), ex->barrierCache.bitPattern[1]); _Unwind_SetIP(ctx, ex->barrierCache.bitPattern[3]); #endif _Unwind_DeleteException(ex); return _URC_INSTALL_CONTEXT; } /* No LSDA -> nothing to handle */ if ((LSDAAddr = _Unwind_GetLanguageSpecificData(ctx)) == NULL) CONTINUE_UNWIND; readLSDA(ctx, LSDAAddr, &LSDA); if (!findCallsite(ctx, &LSDA, &landingpad, &actionRecords)) CONTINUE_UNWIND; if (landingpad != 0 && actionRecords != NULL) found = findActionRecord(actionRecords, &LSDA, actions, foreign, e, &filter); else if (landingpad != 0) found = CLEANUP_FOUND; if (found == 0) CONTINUE_UNWIND; if (actions & _UA_SEARCH_PHASE) { if (!(found & HANDLER_FOUND) || foreign) CONTINUE_UNWIND; /* Cache it so we don't have to search it again in phase 2 */ #ifndef HAVE_ARM_EHABI_EXCEPTIONS e->landingpad = landingpad; e->filter = filter; #else ex->barrierCache.sp = _Unwind_GetGR(ctx, 13); ex->barrierCache.bitPattern[1] = filter; ex->barrierCache.bitPattern[3] = landingpad; #endif return _URC_HANDLER_FOUND; } else if (actions & _UA_CLEANUP_PHASE) { if (!(found & CLEANUP_FOUND)) CONTINUE_UNWIND; _Unwind_SetGR(ctx, __builtin_eh_return_data_regno(0), (uintptr_t)ex); _Unwind_SetGR(ctx, __builtin_eh_return_data_regno(1), filter); _Unwind_SetIP(ctx, landingpad); return _URC_INSTALL_CONTEXT; } OBJC_ERROR( "Neither _UA_SEARCH_PHASE nor _UA_CLEANUP_PHASE in actions!"); } static void cleanup(_Unwind_Reason_Code reason, struct _Unwind_Exception *ex) { free(ex); } static void emergencyExceptionCleanup(_Unwind_Reason_Code reason, struct _Unwind_Exception *ex) { #ifdef OF_HAVE_THREADS if (OFSpinlockLock(&emergencyExceptionsSpinlock) != 0) OBJC_ERROR("Failed to lock spinlock!"); #endif ex->class = 0; #ifdef OF_HAVE_THREADS if (OFSpinlockUnlock(&emergencyExceptionsSpinlock) != 0) OBJC_ERROR("Failed to 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("Failed to lock spinlock!"); #endif for (uint_fast8_t i = 0; i < numEmergencyExceptions; 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("Failed to 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 objc_setUncaughtExceptionHandler(objc_uncaught_exception_handler handler) { objc_uncaught_exception_handler old = uncaughtExceptionHandler; uncaughtExceptionHandler = handler; return old; } #ifdef __SEH__ typedef EXCEPTION_DISPOSITION (*seh_personality_fn)(PEXCEPTION_RECORD, void *, PCONTEXT, PDISPATCHER_CONTEXT); static seh_personality_fn __gxx_personality_seh0; OF_CONSTRUCTOR() { /* * This only works if the application uses libc++.dll or * libstdc++-6.dll. There is unfortunately no other way, as Windows * does not support proper weak linking. */ HMODULE module; module = GetModuleHandle("libc++"); if (module == NULL) module = GetModuleHandle("libstdc++-6"); if (module != NULL) __gxx_personality_seh0 = (seh_personality_fn) GetProcAddress(module, "__gxx_personality_seh0"); } EXCEPTION_DISPOSITION __gnu_objc_personality_seh0(PEXCEPTION_RECORD ms_exc, void *this_frame, PCONTEXT ms_orig_context, PDISPATCHER_CONTEXT ms_disp) { struct _Unwind_Exception *ex = (struct _Unwind_Exception *)ms_exc->ExceptionInformation[0]; switch (ex->class) { case GNUCCXX0_EXCEPTION_CLASS: case CLNGCXX0_EXCEPTION_CLASS: if (__gxx_personality_seh0 != NULL) return __gxx_personality_seh0(ms_exc, this_frame, ms_orig_context, ms_disp); } return _GCC_specific_handler(ms_exc, this_frame, ms_orig_context, ms_disp, PERSONALITY); } #endif