1 files changed, 482 insertions, 0 deletions
diff --git a/src/runtime/signal_windows.go b/src/runtime/signal_windows.go
new file mode 100644
index 0000000..4b7960c
--- /dev/null
+++ b/src/runtime/signal_windows.go
@@ -0,0 +1,482 @@
+// 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 (
+	"internal/abi"
+	"runtime/internal/sys"
+	"unsafe"
+)
+
+const (
+	_SEM_FAILCRITICALERRORS = 0x0001
+	_SEM_NOGPFAULTERRORBOX  = 0x0002
+	_SEM_NOOPENFILEERRORBOX = 0x8000
+
+	_WER_FAULT_REPORTING_NO_UI = 0x0020
+)
+
+func preventErrorDialogs() {
+	errormode := stdcall0(_GetErrorMode)
+	stdcall1(_SetErrorMode, errormode|_SEM_FAILCRITICALERRORS|_SEM_NOGPFAULTERRORBOX|_SEM_NOOPENFILEERRORBOX)
+
+	// Disable WER fault reporting UI.
+	// Do this even if WER is disabled as a whole,
+	// as WER might be enabled later with setTraceback("wer")
+	// and we still want the fault reporting UI to be disabled if this happens.
+	var werflags uintptr
+	stdcall2(_WerGetFlags, currentProcess, uintptr(unsafe.Pointer(&werflags)))
+	stdcall1(_WerSetFlags, werflags|_WER_FAULT_REPORTING_NO_UI)
+}
+
+// enableWER re-enables Windows error reporting without fault reporting UI.
+func enableWER() {
+	// re-enable Windows Error Reporting
+	errormode := stdcall0(_GetErrorMode)
+	if errormode&_SEM_NOGPFAULTERRORBOX != 0 {
+		stdcall1(_SetErrorMode, errormode^_SEM_NOGPFAULTERRORBOX)
+	}
+}
+
+// in sys_windows_386.s, sys_windows_amd64.s, sys_windows_arm.s, and sys_windows_arm64.s
+func exceptiontramp()
+func firstcontinuetramp()
+func lastcontinuetramp()
+func sehtramp()
+func sigresume()
+
+func initExceptionHandler() {
+	stdcall2(_AddVectoredExceptionHandler, 1, abi.FuncPCABI0(exceptiontramp))
+	if GOARCH == "386" {
+		// use SetUnhandledExceptionFilter for windows-386.
+		// note: SetUnhandledExceptionFilter handler won't be called, if debugging.
+		stdcall1(_SetUnhandledExceptionFilter, abi.FuncPCABI0(lastcontinuetramp))
+	} else {
+		stdcall2(_AddVectoredContinueHandler, 1, abi.FuncPCABI0(firstcontinuetramp))
+		stdcall2(_AddVectoredContinueHandler, 0, abi.FuncPCABI0(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" || GOARCH == "arm" {
+		// In the case of an abort, the exception IP is one byte after
+		// the INT3 (this differs from UNIX OSes). Note that on ARM,
+		// this means that the exception IP is no longer aligned.
+		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_IN_PAGE_ERROR:
+	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
+}
+
+const (
+	callbackVEH = iota
+	callbackFirstVCH
+	callbackLastVCH
+)
+
+// sigFetchGSafe is like getg() but without panicking
+// when TLS is not set.
+// Only implemented on windows/386, which is the only
+// arch that loads TLS when calling getg(). Others
+// use a dedicated register.
+func sigFetchGSafe() *g
+
+func sigFetchG() *g {
+	if GOARCH == "386" {
+		return sigFetchGSafe()
+	}
+	return getg()
+}
+
+// sigtrampgo is called from the exception handler function, sigtramp,
+// written in assembly code.
+// Return EXCEPTION_CONTINUE_EXECUTION if the exception is handled,
+// else return EXCEPTION_CONTINUE_SEARCH.
+//
+// It is nosplit for the same reason as exceptionhandler.
+//
+//go:nosplit
+func sigtrampgo(ep *exceptionpointers, kind int) int32 {
+	gp := sigFetchG()
+	if gp == nil {
+		return _EXCEPTION_CONTINUE_SEARCH
+	}
+
+	var fn func(info *exceptionrecord, r *context, gp *g) int32
+	switch kind {
+	case callbackVEH:
+		fn = exceptionhandler
+	case callbackFirstVCH:
+		fn = firstcontinuehandler
+	case callbackLastVCH:
+		fn = lastcontinuehandler
+	default:
+		throw("unknown sigtramp callback")
+	}
+
+	// Check if we are running on g0 stack, and if we are,
+	// call fn directly instead of creating the closure.
+	// for the systemstack argument.
+	//
+	// A closure can't be marked as nosplit, so it might
+	// call morestack if we are at the g0 stack limit.
+	// If that happens, the runtime will call abort
+	// and end up in sigtrampgo again.
+	// TODO: revisit this workaround if/when closures
+	// can be compiled as nosplit.
+	//
+	// Note that this scenario should only occur on
+	// TestG0StackOverflow. Any other occurrence should
+	// be treated as a bug.
+	var ret int32
+	if gp != gp.m.g0 {
+		systemstack(func() {
+			ret = fn(ep.record, ep.context, gp)
+		})
+	} else {
+		ret = fn(ep.record, ep.context, gp)
+	}
+	if ret == _EXCEPTION_CONTINUE_SEARCH {
+		return ret
+	}
+
+	// Check if we need to set up the control flow guard workaround.
+	// On Windows, the stack pointer in the context must lie within
+	// system stack limits when we resume from exception.
+	// Store the resume SP and PC in alternate registers
+	// and return to sigresume on the g0 stack.
+	// sigresume makes no use of the stack at all,
+	// loading SP from RX and jumping to RY, being RX and RY two scratch registers.
+	// Note that blindly smashing RX and RY is only safe because we know sigpanic
+	// will not actually return to the original frame, so the registers
+	// are effectively dead. But this does mean we can't use the
+	// same mechanism for async preemption.
+	if ep.context.ip() == abi.FuncPCABI0(sigresume) {
+		// sigresume has already been set up by a previous exception.
+		return ret
+	}
+	prepareContextForSigResume(ep.context)
+	ep.context.set_sp(gp.m.g0.sched.sp)
+	ep.context.set_ip(abi.FuncPCABI0(sigresume))
+	return ret
+}
+
+// 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 nosplit to avoid growing the stack until we've checked for
+// _EXCEPTION_BREAKPOINT, which is raised by abort() 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() != abi.FuncPCABI0(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(abi.FuncPCABI0(sigpanic0))
+	return _EXCEPTION_CONTINUE_EXECUTION
+}
+
+// sehhandler is reached as part of the SEH chain.
+//
+// It is nosplit for the same reason as exceptionhandler.
+//
+//go:nosplit
+func sehhandler(_ *exceptionrecord, _ uint64, _ *context, dctxt *_DISPATCHER_CONTEXT) int32 {
+	g0 := getg()
+	if g0 == nil || g0.m.curg == nil {
+		// No g available, nothing to do here.
+		return _EXCEPTION_CONTINUE_SEARCH_SEH
+	}
+	// The Windows SEH machinery will unwind the stack until it finds
+	// a frame with a handler for the exception or until the frame is
+	// outside the stack boundaries, in which case it will call the
+	// UnhandledExceptionFilter. Unfortunately, it doesn't know about
+	// the goroutine stack, so it will stop unwinding when it reaches the
+	// first frame not running in g0. As a result, neither non-Go exceptions
+	// handlers higher up the stack nor UnhandledExceptionFilter will be called.
+	//
+	// To work around this, manually unwind the stack until the top of the goroutine
+	// stack is reached, and then pass the control back to Windows.
+	gp := g0.m.curg
+	ctxt := dctxt.ctx()
+	var base, sp uintptr
+	for {
+		entry := stdcall3(_RtlLookupFunctionEntry, ctxt.ip(), uintptr(unsafe.Pointer(&base)), 0)
+		if entry == 0 {
+			break
+		}
+		stdcall8(_RtlVirtualUnwind, 0, base, ctxt.ip(), entry, uintptr(unsafe.Pointer(ctxt)), 0, uintptr(unsafe.Pointer(&sp)), 0)
+		if sp < gp.stack.lo || gp.stack.hi <= sp {
+			break
+		}
+	}
+	return _EXCEPTION_CONTINUE_SEARCH_SEH
+}
+
+// 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
+}
+
+// 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
+	}
+
+	// VEH is called before SEH, but arm64 MSVC DLLs use SEH to trap
+	// illegal instructions during runtime initialization to determine
+	// CPU features, so if we make it to the last handler and we're
+	// arm64 and it's an illegal instruction and this is coming from
+	// non-Go code, then assume it's this runtime probing happen, and
+	// pass that onward to SEH.
+	if GOARCH == "arm64" && info.exceptioncode == _EXCEPTION_ILLEGAL_INSTRUCTION &&
+		(r.ip() < firstmoduledata.text || firstmoduledata.etext < r.ip()) {
+		return _EXCEPTION_CONTINUE_SEARCH
+	}
+
+	winthrow(info, r, gp)
+	return 0 // not reached
+}
+
+// Always called on g0. gp is the G where the exception occurred.
+//
+//go:nosplit
+func winthrow(info *exceptionrecord, r *context, gp *g) {
+	g0 := getg()
+
+	if panicking.Load() != 0 { // traceback already printed
+		exit(2)
+	}
+	panicking.Store(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.
+	g0.stack.lo = 0
+	g0.stackguard0 = g0.stack.lo + stackGuard
+	g0.stackguard1 = g0.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 g0.m.incgo && gp == g0.m.g0 && g0.m.curg != nil {
+		if iscgo {
+			print("signal arrived during external code execution\n")
+		}
+		gp = g0.m.curg
+	}
+	print("\n")
+
+	g0.m.throwing = throwTypeRuntime
+	g0.m.caughtsig.set(gp)
+
+	level, _, docrash := gotraceback()
+	if level > 0 {
+		tracebacktrap(r.ip(), r.sp(), r.lr(), gp)
+		tracebackothers(gp)
+		dumpregs(r)
+	}
+
+	if docrash {
+		dieFromException(info, r)
+	}
+
+	exit(2)
+}
+
+func sigpanic() {
+	gp := getg()
+	if !canpanic() {
+		throw("unexpected signal during runtime execution")
+	}
+
+	switch gp.sig {
+	case _EXCEPTION_ACCESS_VIOLATION, _EXCEPTION_IN_PAGE_ERROR:
+		if gp.sigcode1 < 0x1000 {
+			panicmem()
+		}
+		if gp.paniconfault {
+			panicmemAddr(gp.sigcode1)
+		}
+		if inUserArenaChunk(gp.sigcode1) {
+			// We could check that the arena chunk is explicitly set to fault,
+			// but the fact that we faulted on accessing it is enough to prove
+			// that it is.
+			print("accessed data from freed user arena ", hex(gp.sigcode1), "\n")
+		} else {
+			print("unexpected fault address ", hex(gp.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")
+}
+
+// Following are not implemented.
+
+func initsig(preinit bool) {
+}
+
+func sigenable(sig uint32) {
+}
+
+func sigdisable(sig uint32) {
+}
+
+func sigignore(sig uint32) {
+}
+
+func signame(sig uint32) string {
+	return ""
+}
+
+//go:nosplit
+func crash() {
+	dieFromException(nil, nil)
+}
+
+// dieFromException raises an exception that bypasses all exception handlers.
+// This provides the expected exit status for the shell.
+//
+//go:nosplit
+func dieFromException(info *exceptionrecord, r *context) {
+	if info == nil {
+		gp := getg()
+		if gp.sig != 0 {
+			// Try to reconstruct an exception record from
+			// the exception information stored in gp.
+			info = &exceptionrecord{
+				exceptionaddress: gp.sigpc,
+				exceptioncode:    gp.sig,
+				numberparameters: 2,
+			}
+			info.exceptioninformation[0] = gp.sigcode0
+			info.exceptioninformation[1] = gp.sigcode1
+		} else {
+			// By default, a failing Go application exits with exit code 2.
+			// Use this value when gp does not contain exception info.
+			info = &exceptionrecord{
+				exceptioncode: 2,
+			}
+		}
+	}
+	const FAIL_FAST_GENERATE_EXCEPTION_ADDRESS = 0x1
+	stdcall3(_RaiseFailFastException, uintptr(unsafe.Pointer(info)), uintptr(unsafe.Pointer(r)), FAIL_FAST_GENERATE_EXCEPTION_ADDRESS)
+}
+
+// gsignalStack is unused on Windows.
+type gsignalStack struct{}