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Diffstat (limited to 'src/VBox/Runtime/common/compiler/vcc/except-seh-vcc.cpp')
| -rw-r--r-- | src/VBox/Runtime/common/compiler/vcc/except-seh-vcc.cpp | 243 |
1 files changed, 243 insertions, 0 deletions
diff --git a/src/VBox/Runtime/common/compiler/vcc/except-seh-vcc.cpp b/src/VBox/Runtime/common/compiler/vcc/except-seh-vcc.cpp new file mode 100644 index 00000000..3a873673 --- /dev/null +++ b/src/VBox/Runtime/common/compiler/vcc/except-seh-vcc.cpp @@ -0,0 +1,243 @@ +/* $Id: except-seh-vcc.cpp $ */ +/** @file + * IPRT - Visual C++ Compiler - SEH exception handler (__try/__except/__finally). + */ + +/* + * Copyright (C) 2022-2023 Oracle and/or its affiliates. + * + * This file is part of VirtualBox base platform packages, as + * available from https://www.virtualbox.org. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation, in version 3 of the + * License. + * + * 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 + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, see <https://www.gnu.org/licenses>. + * + * The contents of this file may alternatively be used under the terms + * of the Common Development and Distribution License Version 1.0 + * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included + * in the VirtualBox distribution, in which case the provisions of the + * CDDL are applicable instead of those of the GPL. + * + * You may elect to license modified versions of this file under the + * terms and conditions of either the GPL or the CDDL or both. + * + * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0 + */ + + +/********************************************************************************************************************************* +* Header Files * +*********************************************************************************************************************************/ +#include "internal/nocrt.h" + +#include "except-vcc.h" + + +#if !defined(RT_ARCH_AMD64) +# error "This file is for AMD64 (and probably ARM, but needs porting)" +#endif + + +/** + * Calls an exception filter w/o doing any control guard checks. + * + * Doing this within an inline function to prevent disabling CFG for any other + * calls that __C_specific_handler might be doing. + * + * Presumably, the presumption here is that since the target address here is + * taken from tables assumed to be readonly and generated by the compiler, there + * is no need to do any CFG checks. Besides, the target isn't a function that + * is safe to be called out of context and thus doesn't belong in the CFG tables + * in any way. + */ +__declspec(guard(ignore)) +DECLINLINE(LONG) CallFilterFunction(PEXCEPTION_FILTER pfnFilter, PEXCEPTION_POINTERS pXcptPtrs, + PEXCEPTION_REGISTRATION_RECORD pXcptRegRec) +{ + return pfnFilter(pXcptPtrs, pXcptRegRec); +} + + +/** + * Calls an exception finally block w/o doing any control guard checks. + * + * See CallFilterFunction for details. + */ +__declspec(guard(ignore)) +DECLINLINE(void) CallFinallyFunction(PTERMINATION_HANDLER const pfnTermHandler, BOOLEAN fAbend, + PEXCEPTION_REGISTRATION_RECORD pXcptRegRec) +{ + pfnTermHandler(fAbend, pXcptRegRec); +} + + +/** + * Call exception filters, handlers and unwind code. + * + * This is called for windows' structured exception handling (SEH), i.e. the + * __try/__except/__finally stuff in Visual C++. The compiler generate scope + * records for the __try/__except blocks as well as unwind records for __finally + * and probably C++ stack object destructors. + * + * @returns Exception disposition. + * @param pXcptRec The exception record. + * @param pXcptRegRec The exception registration record, taken to be the frame + * address. + * @param pCpuCtx The CPU context for the exception. + * @param pDispCtx Dispatcher context. + */ +EXCEPTION_DISPOSITION __C_specific_handler(PEXCEPTION_RECORD pXcptRec, PEXCEPTION_REGISTRATION_RECORD pXcptRegRec, + PCONTEXT pCpuCtx, PDISPATCHER_CONTEXT pDispCtx) +{ + /* + * This function works the scope table, starting at ScopeIndex + * from the dispatcher context. + */ + SCOPE_TABLE const * const pScopeTab = (SCOPE_TABLE const *)pDispCtx->HandlerData; + uint32_t const cScopes = pScopeTab->Count; + uint32_t idxScope = pDispCtx->ScopeIndex; + + /* + * The table addresses are RVAs, so convert the program counter (PC) to an RVA. + */ + uint32_t const uRvaPc = pDispCtx->ControlPc - pDispCtx->ImageBase; + + /* + * Before we get any further, there are two types of scope records: + * 1. Unwind (aka termination) handler (JumpTarget == 0). + * 2. Exception filter & handler (JumpTarget != 0). + */ + + if (IS_DISPATCHING(pXcptRec->ExceptionFlags)) + { + /* + * Call exception filter functions when dispatching. + */ + for (; idxScope < cScopes; idxScope++) + { + /* Skip unwind entries (exception handler set to zero). */ + uint32_t const uXcptHandler = pScopeTab->ScopeRecord[idxScope].JumpTarget; + if (uXcptHandler != 0) + { + uint32_t const uBegin = pScopeTab->ScopeRecord[idxScope].BeginAddress; + uint32_t const uEnd = pScopeTab->ScopeRecord[idxScope].EndAddress; + uint32_t const cbScope = uEnd - uBegin; + if ( uRvaPc - uBegin < cbScope + && uBegin < uEnd /* paranoia */) + { + /* The special HandlerAddress value 1 translates to a + EXCEPTION_EXECUTE_HANDLER filter return value. */ + LONG lRet = EXCEPTION_EXECUTE_HANDLER; + uint32_t const uFltTermHandler = pScopeTab->ScopeRecord[idxScope].HandlerAddress; + if (uFltTermHandler != 1) + { + PEXCEPTION_FILTER const pfnFilter = (PEXCEPTION_FILTER)(pDispCtx->ImageBase + uFltTermHandler); + EXCEPTION_POINTERS XcptPtrs = { pXcptRec, pCpuCtx }; + lRet = CallFilterFunction(pfnFilter, &XcptPtrs, pXcptRegRec); + + AssertCompile(EXCEPTION_CONTINUE_SEARCH == 0); + if (lRet == EXCEPTION_CONTINUE_SEARCH) + continue; + } + + /* Return if we're supposed to continue execution (the convention + it to match negative values rather than the exact defined value): */ + AssertCompile(EXCEPTION_CONTINUE_EXECUTION == -1); + AssertCompile(EXCEPTION_EXECUTE_HANDLER == 1); + if (lRet <= EXCEPTION_CONTINUE_EXECUTION) + return ExceptionContinueExecution; + + /* Execute the handler (lRet >= EXCEPTION_EXECUTE_HANDLER). */ + uintptr_t const uPtrXcptHandler = uXcptHandler + pDispCtx->ImageBase; + /** @todo shouldn't we do a guard check on this call? */ + + /// @todo _NLG_Notify(uPtrXcptHandler, pXcptRegRec, 1); - debugger notification. + + RtlUnwindEx(pXcptRegRec, (void *)uPtrXcptHandler, pXcptRec, + (PVOID)(uintptr_t)pXcptRec->ExceptionCode, pCpuCtx, pDispCtx->HistoryTable); + + /// @todo _NLG_Return2(); - debugger notification. + } + } + } + } + else + { + /* + * Do unwinding. + */ + + /* Convert the target unwind address to an RVA up front for efficiency. + (I think target unwinding is what the RtlUnwindEx call above does.) */ + uint32_t const uTargetPc = pXcptRec->ExceptionFlags & EXCEPTION_TARGET_UNWIND + ? pDispCtx->TargetIp - pDispCtx->ImageBase + : UINT32_MAX; + //RTAssertMsg2("__C_specific_handler: unwind: idxScope=%#x cScopes=%#x uTargetPc=%#x fXcpt=%#x\n", idxScope, cScopes, uTargetPc, pXcptRec->ExceptionFlags); + + for (; idxScope < cScopes; idxScope++) + { + uint32_t const uBegin = pScopeTab->ScopeRecord[idxScope].BeginAddress; + uint32_t const uEnd = pScopeTab->ScopeRecord[idxScope].EndAddress; + uint32_t const cbScope = uEnd - uBegin; + if ( uRvaPc - uBegin < cbScope + && uBegin < uEnd /* paranoia */) + { + uint32_t const uFltTermHandler = pScopeTab->ScopeRecord[idxScope].HandlerAddress; + uint32_t const uXcptHandler = pScopeTab->ScopeRecord[idxScope].JumpTarget; + + /* Target unwind requires us to stop if the target PC is in the same + scope as the control PC. Happens for goto out of inner __try scope + or when longjmp'ing into a __try scope. */ + if (pXcptRec->ExceptionFlags & EXCEPTION_TARGET_UNWIND) + { + /* The scope same-ness is identified by the same handler and jump target rva values. */ + for (uint32_t idxTgtScope = 0; idxTgtScope < cScopes; idxTgtScope++) + if ( pScopeTab->ScopeRecord[idxTgtScope].JumpTarget == uXcptHandler + && pScopeTab->ScopeRecord[idxTgtScope].HandlerAddress == uFltTermHandler) + { + uint32_t const uTgtBegin = pScopeTab->ScopeRecord[idxTgtScope].BeginAddress; + uint32_t const uTgtEnd = pScopeTab->ScopeRecord[idxTgtScope].EndAddress; + uint32_t const cbTgtScope = uTgtEnd - uTgtBegin; + if ( uTargetPc - uTgtBegin < cbTgtScope + && uTgtBegin < uTgtEnd /* paranoia */) + { + //RTAssertMsg2("__C_specific_handler: ExceptionContinueSearch (#1)\n"); + return ExceptionContinueSearch; + } + } + } + + /* The unwind handlers are what we're here for. */ + if (uXcptHandler == 0) + { + PTERMINATION_HANDLER const pfnTermHandler = (PTERMINATION_HANDLER)(pDispCtx->ImageBase + uFltTermHandler); + pDispCtx->ScopeIndex = idxScope + 1; + //RTAssertMsg2("__C_specific_handler: Calling __finally %p (idxScope=%#x)\n", pfnTermHandler, idxScope); + CallFinallyFunction(pfnTermHandler, TRUE /*fAbend*/, pXcptRegRec); + } + /* Exception filter & handler entries are skipped, unless the exception + handler is being targeted by the unwind, in which case we're done + unwinding and the caller should transfer control there. */ + else if ( uXcptHandler == uTargetPc + && (pXcptRec->ExceptionFlags & EXCEPTION_TARGET_UNWIND)) + { + //RTAssertMsg2("__C_specific_handler: ExceptionContinueSearch (#2)\n"); + return ExceptionContinueSearch; + } + } + } + } + + return ExceptionContinueSearch; +} + |