src/runtime/signal_windows.go - go - Git at Google

 // Copyright 2011 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.

 package runtime

 import (
 	"runtime/internal/sys"
 	"unsafe"
 )

 func disableWER() {
 	// do not display Windows Error Reporting dialogue
 	const (
 		SEM_FAILCRITICALERRORS     = 0x0001
 		SEM_NOGPFAULTERRORBOX      = 0x0002
 		SEM_NOALIGNMENTFAULTEXCEPT = 0x0004
 		SEM_NOOPENFILEERRORBOX     = 0x8000
 	)
 	errormode := uint32(stdcall1(_SetErrorMode, SEM_NOGPFAULTERRORBOX))
 	stdcall1(_SetErrorMode, uintptr(errormode)|SEM_FAILCRITICALERRORS|SEM_NOGPFAULTERRORBOX|SEM_NOOPENFILEERRORBOX)
 }

 // in sys_windows_386.s and sys_windows_amd64.s
 func exceptiontramp()
 func firstcontinuetramp()
 func lastcontinuetramp()

 func initExceptionHandler() {
 	stdcall2(_AddVectoredExceptionHandler, 1, funcPC(exceptiontramp))
 	if _AddVectoredContinueHandler == nil || GOARCH == "386" {
 		// use SetUnhandledExceptionFilter for windows-386 or
 		// if VectoredContinueHandler is unavailable.
 		// note: SetUnhandledExceptionFilter handler won't be called, if debugging.
 		stdcall1(_SetUnhandledExceptionFilter, funcPC(lastcontinuetramp))
 	} else {
 		stdcall2(_AddVectoredContinueHandler, 1, funcPC(firstcontinuetramp))
 		stdcall2(_AddVectoredContinueHandler, 0, funcPC(lastcontinuetramp))
 	}
 }

 // isAbort returns true, if context r describes exception raised
 // by calling runtime.abort function.
 //
 //go:nosplit
 func isAbort(r *context) bool {
 	pc := r.ip()
 	if GOARCH == "386" || GOARCH == "amd64" {
 		// In the case of an abort, the exception IP is one byte after
 		// the INT3 (this differs from UNIX OSes).
 		pc--
 	}
 	return isAbortPC(pc)
 }

 // isgoexception reports whether this exception should be translated
 // into a Go panic or throw.
 //
 // It is nosplit to avoid growing the stack in case we're aborting
 // because of a stack overflow.
 //
 //go:nosplit
 func isgoexception(info *exceptionrecord, r *context) bool {
 	// Only handle exception if executing instructions in Go binary
 	// (not Windows library code).
 	// TODO(mwhudson): needs to loop to support shared libs
 	if r.ip() < firstmoduledata.text || firstmoduledata.etext < r.ip() {
 		return false
 	}

 	// Go will only handle some exceptions.
 	switch info.exceptioncode {
 	default:
 		return false
 	case _EXCEPTION_ACCESS_VIOLATION:
 	case _EXCEPTION_INT_DIVIDE_BY_ZERO:
 	case _EXCEPTION_INT_OVERFLOW:
 	case _EXCEPTION_FLT_DENORMAL_OPERAND:
 	case _EXCEPTION_FLT_DIVIDE_BY_ZERO:
 	case _EXCEPTION_FLT_INEXACT_RESULT:
 	case _EXCEPTION_FLT_OVERFLOW:
 	case _EXCEPTION_FLT_UNDERFLOW:
 	case _EXCEPTION_BREAKPOINT:
 	case _EXCEPTION_ILLEGAL_INSTRUCTION: // breakpoint arrives this way on arm64
 	}
 	return true
 }

 // Called by sigtramp from Windows VEH handler.
 // Return value signals whether the exception has been handled (EXCEPTION_CONTINUE_EXECUTION)
 // or should be made available to other handlers in the chain (EXCEPTION_CONTINUE_SEARCH).
 //
 // This is the first entry into Go code for exception handling. This
 // is nosplit to avoid growing the stack until we've checked for
 // _EXCEPTION_BREAKPOINT, which is raised if we overflow the g0 stack,
 //
 //go:nosplit
 func exceptionhandler(info *exceptionrecord, r *context, gp *g) int32 {
 	if !isgoexception(info, r) {
 		return _EXCEPTION_CONTINUE_SEARCH
 	}

 	if gp.throwsplit || isAbort(r) {
 		// We can't safely sigpanic because it may grow the stack.
 		// Or this is a call to abort.
 		// Don't go through any more of the Windows handler chain.
 		// Crash now.
 		winthrow(info, r, gp)
 	}

 	// After this point, it is safe to grow the stack.

 	// Make it look like a call to the signal func.
 	// Have to pass arguments out of band since
 	// augmenting the stack frame would break
 	// the unwinding code.
 	gp.sig = info.exceptioncode
 	gp.sigcode0 = info.exceptioninformation[0]
 	gp.sigcode1 = info.exceptioninformation[1]
 	gp.sigpc = r.ip()

 	// Only push runtime·sigpanic if r.ip() != 0.
 	// If r.ip() == 0, probably panicked because of a
 	// call to a nil func. Not pushing that onto sp will
 	// make the trace look like a call to runtime·sigpanic instead.
 	// (Otherwise the trace will end at runtime·sigpanic and we
 	// won't get to see who faulted.)
 	// Also don't push a sigpanic frame if the faulting PC
 	// is the entry of asyncPreempt. In this case, we suspended
 	// the thread right between the fault and the exception handler
 	// starting to run, and we have pushed an asyncPreempt call.
 	// The exception is not from asyncPreempt, so not to push a
 	// sigpanic call to make it look like that. Instead, just
 	// overwrite the PC. (See issue #35773)
 	if r.ip() != 0 && r.ip() != funcPC(asyncPreempt) {
 		sp := unsafe.Pointer(r.sp())
 		delta := uintptr(sys.StackAlign)
 		sp = add(sp, -delta)
 		r.set_sp(uintptr(sp))
 		if usesLR {
 			*((*uintptr)(sp)) = r.lr()
 			r.set_lr(r.ip())
 		} else {
 			*((*uintptr)(sp)) = r.ip()
 		}
 	}
 	r.set_ip(funcPC(sigpanic))
 	return _EXCEPTION_CONTINUE_EXECUTION
 }

 // It seems Windows searches ContinueHandler's list even
 // if ExceptionHandler returns EXCEPTION_CONTINUE_EXECUTION.
 // firstcontinuehandler will stop that search,
 // if exceptionhandler did the same earlier.
 //
 // It is nosplit for the same reason as exceptionhandler.
 //
 //go:nosplit
 func firstcontinuehandler(info *exceptionrecord, r *context, gp *g) int32 {
 	if !isgoexception(info, r) {
 		return _EXCEPTION_CONTINUE_SEARCH
 	}
 	return _EXCEPTION_CONTINUE_EXECUTION
 }

 var testingWER bool

 // lastcontinuehandler is reached, because runtime cannot handle
 // current exception. lastcontinuehandler will print crash info and exit.
 //
 // It is nosplit for the same reason as exceptionhandler.
 //
 //go:nosplit
 func lastcontinuehandler(info *exceptionrecord, r *context, gp *g) int32 {
 	if islibrary || isarchive {
 		// Go DLL/archive has been loaded in a non-go program.
 		// If the exception does not originate from go, the go runtime
 		// should not take responsibility of crashing the process.
 		return _EXCEPTION_CONTINUE_SEARCH
 	}
 	if testingWER {
 		return _EXCEPTION_CONTINUE_SEARCH
 	}

 	winthrow(info, r, gp)
 	return 0 // not reached
 }

 //go:nosplit
 func winthrow(info *exceptionrecord, r *context, gp *g) {
 	_g_ := getg()

 	if panicking != 0 { // traceback already printed
 		exit(2)
 	}
 	panicking = 1

 	// In case we're handling a g0 stack overflow, blow away the
 	// g0 stack bounds so we have room to print the traceback. If
 	// this somehow overflows the stack, the OS will trap it.
 	_g_.stack.lo = 0
 	_g_.stackguard0 = _g_.stack.lo + _StackGuard
 	_g_.stackguard1 = _g_.stackguard0

 	print("Exception ", hex(info.exceptioncode), " ", hex(info.exceptioninformation[0]), " ", hex(info.exceptioninformation[1]), " ", hex(r.ip()), "\n")

 	print("PC=", hex(r.ip()), "\n")
 	if _g_.m.lockedg != 0 && _g_.m.ncgo > 0 && gp == _g_.m.g0 {
 		if iscgo {
 			print("signal arrived during external code execution\n")
 		}
 		gp = _g_.m.lockedg.ptr()
 	}
 	print("\n")

 	_g_.m.throwing = 1
 	_g_.m.caughtsig.set(gp)

 	level, _, docrash := gotraceback()
 	if level > 0 {
 		tracebacktrap(r.ip(), r.sp(), r.lr(), gp)
 		tracebackothers(gp)
 		dumpregs(r)
 	}

 	if docrash {
 		crash()
 	}

 	exit(2)
 }

 func sigpanic() {
 	g := getg()
 	if !canpanic(g) {
 		throw("unexpected signal during runtime execution")
 	}

 	switch g.sig {
 	case _EXCEPTION_ACCESS_VIOLATION:
 		if g.sigcode1 < 0x1000 {
 			panicmem()
 		}
 		if g.paniconfault {
 			panicmemAddr(g.sigcode1)
 		}
 		print("unexpected fault address ", hex(g.sigcode1), "\n")
 		throw("fault")
 	case _EXCEPTION_INT_DIVIDE_BY_ZERO:
 		panicdivide()
 	case _EXCEPTION_INT_OVERFLOW:
 		panicoverflow()
 	case _EXCEPTION_FLT_DENORMAL_OPERAND,
 		_EXCEPTION_FLT_DIVIDE_BY_ZERO,
 		_EXCEPTION_FLT_INEXACT_RESULT,
 		_EXCEPTION_FLT_OVERFLOW,
 		_EXCEPTION_FLT_UNDERFLOW:
 		panicfloat()
 	}
 	throw("fault")
 }

 var (
 	badsignalmsg [100]byte
 	badsignallen int32
 )

 func setBadSignalMsg() {
 	const msg = "runtime: signal received on thread not created by Go.\n"
 	for i, c := range msg {
 		badsignalmsg[i] = byte(c)
 		badsignallen++
 	}
 }

 // Following are not implemented.

 func initsig(preinit bool) {
 }

 func sigenable(sig uint32) {
 }

 func sigdisable(sig uint32) {
 }

 func sigignore(sig uint32) {
 }

 func badsignal2()

 func raisebadsignal(sig uint32) {
 	badsignal2()
 }

 func signame(sig uint32) string {
 	return ""
 }

 //go:nosplit
 func crash() {
 	// TODO: This routine should do whatever is needed
 	// to make the Windows program abort/crash as it
 	// would if Go was not intercepting signals.
 	// On Unix the routine would remove the custom signal
 	// handler and then raise a signal (like SIGABRT).
 	// Something like that should happen here.
 	// It's okay to leave this empty for now: if crash returns
 	// the ordinary exit-after-panic happens.
 }

 // gsignalStack is unused on Windows.
 type gsignalStack struct{}
	// Copyright 2011 The Go Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style
	// license that can be found in the LICENSE file.

	package runtime

	import (
	"runtime/internal/sys"
	"unsafe"
	)

	func disableWER() {
	// do not display Windows Error Reporting dialogue
	const (
	SEM_FAILCRITICALERRORS = 0x0001
	SEM_NOGPFAULTERRORBOX = 0x0002
	SEM_NOALIGNMENTFAULTEXCEPT = 0x0004
	SEM_NOOPENFILEERRORBOX = 0x8000
	)
	errormode := uint32(stdcall1(_SetErrorMode, SEM_NOGPFAULTERRORBOX))
	stdcall1(_SetErrorMode, uintptr(errormode)\|SEM_FAILCRITICALERRORS\|SEM_NOGPFAULTERRORBOX\|SEM_NOOPENFILEERRORBOX)
	}

	// in sys_windows_386.s and sys_windows_amd64.s
	func exceptiontramp()
	func firstcontinuetramp()
	func lastcontinuetramp()

	func initExceptionHandler() {
	stdcall2(_AddVectoredExceptionHandler, 1, funcPC(exceptiontramp))
	if _AddVectoredContinueHandler == nil \|\| GOARCH == "386" {
	// use SetUnhandledExceptionFilter for windows-386 or
	// if VectoredContinueHandler is unavailable.
	// note: SetUnhandledExceptionFilter handler won't be called, if debugging.
	stdcall1(_SetUnhandledExceptionFilter, funcPC(lastcontinuetramp))
	} else {
	stdcall2(_AddVectoredContinueHandler, 1, funcPC(firstcontinuetramp))
	stdcall2(_AddVectoredContinueHandler, 0, funcPC(lastcontinuetramp))
	}
	}

	// isAbort returns true, if context r describes exception raised
	// by calling runtime.abort function.
	//
	//go:nosplit
	func isAbort(r *context) bool {
	pc := r.ip()
	if GOARCH == "386" \|\| GOARCH == "amd64" {
	// In the case of an abort, the exception IP is one byte after
	// the INT3 (this differs from UNIX OSes).
	pc--
	}
	return isAbortPC(pc)
	}

	// isgoexception reports whether this exception should be translated
	// into a Go panic or throw.
	//
	// It is nosplit to avoid growing the stack in case we're aborting
	// because of a stack overflow.
	//
	//go:nosplit
	func isgoexception(info exceptionrecord, r context) bool {
	// Only handle exception if executing instructions in Go binary
	// (not Windows library code).
	// TODO(mwhudson): needs to loop to support shared libs
	if r.ip() < firstmoduledata.text \|\| firstmoduledata.etext < r.ip() {
	return false
	}

	// Go will only handle some exceptions.
	switch info.exceptioncode {
	default:
	return false
	case _EXCEPTION_ACCESS_VIOLATION:
	case _EXCEPTION_INT_DIVIDE_BY_ZERO:
	case _EXCEPTION_INT_OVERFLOW:
	case _EXCEPTION_FLT_DENORMAL_OPERAND:
	case _EXCEPTION_FLT_DIVIDE_BY_ZERO:
	case _EXCEPTION_FLT_INEXACT_RESULT:
	case _EXCEPTION_FLT_OVERFLOW:
	case _EXCEPTION_FLT_UNDERFLOW:
	case _EXCEPTION_BREAKPOINT:
	case _EXCEPTION_ILLEGAL_INSTRUCTION: // breakpoint arrives this way on arm64
	}
	return true
	}

	// Called by sigtramp from Windows VEH handler.
	// Return value signals whether the exception has been handled (EXCEPTION_CONTINUE_EXECUTION)
	// or should be made available to other handlers in the chain (EXCEPTION_CONTINUE_SEARCH).
	//
	// This is the first entry into Go code for exception handling. This
	// is nosplit to avoid growing the stack until we've checked for
	// _EXCEPTION_BREAKPOINT, which is raised if we overflow the g0 stack,
	//
	//go:nosplit
	func exceptionhandler(info exceptionrecord, r context, gp *g) int32 {
	if !isgoexception(info, r) {
	return _EXCEPTION_CONTINUE_SEARCH
	}

	if gp.throwsplit \|\| isAbort(r) {
	// We can't safely sigpanic because it may grow the stack.
	// Or this is a call to abort.
	// Don't go through any more of the Windows handler chain.
	// Crash now.
	winthrow(info, r, gp)
	}

	// After this point, it is safe to grow the stack.

	// Make it look like a call to the signal func.
	// Have to pass arguments out of band since
	// augmenting the stack frame would break
	// the unwinding code.
	gp.sig = info.exceptioncode
	gp.sigcode0 = info.exceptioninformation[0]
	gp.sigcode1 = info.exceptioninformation[1]
	gp.sigpc = r.ip()

	// Only push runtime·sigpanic if r.ip() != 0.
	// If r.ip() == 0, probably panicked because of a
	// call to a nil func. Not pushing that onto sp will
	// make the trace look like a call to runtime·sigpanic instead.
	// (Otherwise the trace will end at runtime·sigpanic and we
	// won't get to see who faulted.)
	// Also don't push a sigpanic frame if the faulting PC
	// is the entry of asyncPreempt. In this case, we suspended
	// the thread right between the fault and the exception handler
	// starting to run, and we have pushed an asyncPreempt call.
	// The exception is not from asyncPreempt, so not to push a
	// sigpanic call to make it look like that. Instead, just
	// overwrite the PC. (See issue #35773)
	if r.ip() != 0 && r.ip() != funcPC(asyncPreempt) {
	sp := unsafe.Pointer(r.sp())
	delta := uintptr(sys.StackAlign)
	sp = add(sp, -delta)
	r.set_sp(uintptr(sp))
	if usesLR {
	((uintptr)(sp)) = r.lr()
	r.set_lr(r.ip())
	} else {
	((uintptr)(sp)) = r.ip()
	}
	}
	r.set_ip(funcPC(sigpanic))
	return _EXCEPTION_CONTINUE_EXECUTION
	}

	// It seems Windows searches ContinueHandler's list even
	// if ExceptionHandler returns EXCEPTION_CONTINUE_EXECUTION.
	// firstcontinuehandler will stop that search,
	// if exceptionhandler did the same earlier.
	//
	// It is nosplit for the same reason as exceptionhandler.
	//
	//go:nosplit
	func firstcontinuehandler(info exceptionrecord, r context, gp *g) int32 {
	if !isgoexception(info, r) {
	return _EXCEPTION_CONTINUE_SEARCH
	}
	return _EXCEPTION_CONTINUE_EXECUTION
	}

	var testingWER bool

	// lastcontinuehandler is reached, because runtime cannot handle
	// current exception. lastcontinuehandler will print crash info and exit.
	//
	// It is nosplit for the same reason as exceptionhandler.
	//
	//go:nosplit
	func lastcontinuehandler(info exceptionrecord, r context, gp *g) int32 {
	if islibrary \|\| isarchive {
	// Go DLL/archive has been loaded in a non-go program.
	// If the exception does not originate from go, the go runtime
	// should not take responsibility of crashing the process.
	return _EXCEPTION_CONTINUE_SEARCH
	}
	if testingWER {
	return _EXCEPTION_CONTINUE_SEARCH
	}

	winthrow(info, r, gp)
	return 0 // not reached
	}

	//go:nosplit
	func winthrow(info exceptionrecord, r context, gp *g) {
	_g_ := getg()

	if panicking != 0 { // traceback already printed
	exit(2)
	}
	panicking = 1

	// In case we're handling a g0 stack overflow, blow away the
	// g0 stack bounds so we have room to print the traceback. If
	// this somehow overflows the stack, the OS will trap it.
	_g_.stack.lo = 0
	_g_.stackguard0 = _g_.stack.lo + _StackGuard
	_g_.stackguard1 = _g_.stackguard0

	print("Exception ", hex(info.exceptioncode), " ", hex(info.exceptioninformation[0]), " ", hex(info.exceptioninformation[1]), " ", hex(r.ip()), "\n")

	print("PC=", hex(r.ip()), "\n")
	if _g_.m.lockedg != 0 && _g_.m.ncgo > 0 && gp == _g_.m.g0 {
	if iscgo {
	print("signal arrived during external code execution\n")
	}
	gp = _g_.m.lockedg.ptr()
	}
	print("\n")

	_g_.m.throwing = 1
	_g_.m.caughtsig.set(gp)

	level, _, docrash := gotraceback()
	if level > 0 {
	tracebacktrap(r.ip(), r.sp(), r.lr(), gp)
	tracebackothers(gp)
	dumpregs(r)
	}

	if docrash {
	crash()
	}

	exit(2)
	}

	func sigpanic() {
	g := getg()
	if !canpanic(g) {
	throw("unexpected signal during runtime execution")
	}

	switch g.sig {
	case _EXCEPTION_ACCESS_VIOLATION:
	if g.sigcode1 < 0x1000 {
	panicmem()
	}
	if g.paniconfault {
	panicmemAddr(g.sigcode1)
	}
	print("unexpected fault address ", hex(g.sigcode1), "\n")
	throw("fault")
	case _EXCEPTION_INT_DIVIDE_BY_ZERO:
	panicdivide()
	case _EXCEPTION_INT_OVERFLOW:
	panicoverflow()
	case _EXCEPTION_FLT_DENORMAL_OPERAND,
	_EXCEPTION_FLT_DIVIDE_BY_ZERO,
	_EXCEPTION_FLT_INEXACT_RESULT,
	_EXCEPTION_FLT_OVERFLOW,
	_EXCEPTION_FLT_UNDERFLOW:
	panicfloat()
	}
	throw("fault")
	}

	var (
	badsignalmsg [100]byte
	badsignallen int32
	)

	func setBadSignalMsg() {
	const msg = "runtime: signal received on thread not created by Go.\n"
	for i, c := range msg {
	badsignalmsg[i] = byte(c)
	badsignallen++
	}
	}

	// Following are not implemented.

	func initsig(preinit bool) {
	}

	func sigenable(sig uint32) {
	}

	func sigdisable(sig uint32) {
	}

	func sigignore(sig uint32) {
	}

	func badsignal2()

	func raisebadsignal(sig uint32) {
	badsignal2()
	}

	func signame(sig uint32) string {
	return ""
	}

	//go:nosplit
	func crash() {
	// TODO: This routine should do whatever is needed
	// to make the Windows program abort/crash as it
	// would if Go was not intercepting signals.
	// On Unix the routine would remove the custom signal
	// handler and then raise a signal (like SIGABRT).
	// Something like that should happen here.
	// It's okay to leave this empty for now: if crash returns
	// the ordinary exit-after-panic happens.
	}

	// gsignalStack is unused on Windows.
	type gsignalStack struct{}