Pull sync generated syscalls

This moves all the current users of
$GOROOT/src/syscall/mksyscall_windows.go to instead use
golang.org/x/sys/windows/mkwinsyscall, as directed by the version of the
former in Go 1.15.

It also syncs the local forks of mksyscall_windows.go with the latest
version of golang.org/x/sys/windows/mkwinsyscall/mkwinsyscall.go, so
that the local patches can be easily seen in a side-by-side comparison.
Significant changes compared to the in-tree forked versions:
* *bool parameters are read back through a temp-var, not directly like
  other pointer parameters.
* ?-suffixed function names support testing for function presence before
  calling. This replaces a local implementation of this in
  pkg/security, which was not actually used anyway. The upstream version
  correctly supports functions that don't already have an error return.
* `errnoErr(0)` is now useful, so each call of `errnoErr` doesn't need
  to be protected with a check for 0 first.
* The generated functions are now sorted. This of course produced a
  *lot* of churn in the generated files.

vhd\vhd.go was changed to generate syscalls into zvhd_windows.go, since
regeneration removes the build tag added by hand in
9d8277341f.

After all that, I also ran
```
go generate . .\pkg\etw\ .\pkg\process\ .\pkg\security\ .\vhd\
```
to update all the existing generated code.

Signed-off-by: Paul "TBBle" Hampson <Paul.Hampson@Pobox.com>

pkg/etw/mksyscall_windows.go

@@ -33,6 +33,9 @@ like func declarations if //sys is replaced by func, but:
   //sys LoadLibrary(libname string) (handle uint32, err error) [failretval==-1] = LoadLibraryA
   and is [failretval==0] by default.
 
+* If the function name ends in a "?", then the function not existing is non-
+  fatal, and an error will be returned instead of panicking.
+
 Usage:
 	mksyscall_windows [flags] [path ...]
 
@@ -107,14 +110,20 @@ func (p *Param) tmpVar() string {
 
 // BoolTmpVarCode returns source code for bool temp variable.
 func (p *Param) BoolTmpVarCode() string {
-	const code = `var %s uint32
-	if %s {
-		%s = 1
-	} else {
-		%s = 0
+	const code = `var %[1]s uint32
+	if %[2]s {
+		%[1]s = 1
 	}`
-	tmp := p.tmpVar()
-	return fmt.Sprintf(code, tmp, p.Name, tmp, tmp)
+	return fmt.Sprintf(code, p.tmpVar(), p.Name)
+}
+
+// BoolPointerTmpVarCode returns source code for bool temp variable.
+func (p *Param) BoolPointerTmpVarCode() string {
+	const code = `var %[1]s uint32
+	if *%[2]s {
+		%[1]s = 1
+	}`
+	return fmt.Sprintf(code, p.tmpVar(), p.Name)
 }
 
 // SliceTmpVarCode returns source code for slice temp variable.
@@ -152,6 +161,8 @@ func (p *Param) TmpVarCode() string {
 	switch {
 	case p.Type == "bool":
 		return p.BoolTmpVarCode()
+	case p.Type == "*bool":
+		return p.BoolPointerTmpVarCode()
 	case strings.HasPrefix(p.Type, "[]"):
 		return p.SliceTmpVarCode()
 	default:
@@ -159,6 +170,16 @@ func (p *Param) TmpVarCode() string {
 	}
 }
 
+// TmpVarReadbackCode returns source code for reading back the temp variable into the original variable.
+func (p *Param) TmpVarReadbackCode() string {
+	switch {
+	case p.Type == "*bool":
+		return fmt.Sprintf("*%s = %s != 0", p.Name, p.tmpVar())
+	default:
+		return ""
+	}
+}
+
 // TmpVarHelperCode returns source code for helper's temp variable.
 func (p *Param) TmpVarHelperCode() string {
 	if p.Type != "string" {
@@ -174,6 +195,8 @@ func (p *Param) SyscallArgList() []string {
 	t := p.HelperType()
 	var s string
 	switch {
+	case t == "*bool":
+		s = fmt.Sprintf("unsafe.Pointer(&%s)", p.tmpVar())
 	case t[0] == '*':
 		s = fmt.Sprintf("unsafe.Pointer(%s)", p.Name)
 	case t == "bool":
@@ -218,10 +241,11 @@ func join(ps []*Param, fn func(*Param) string, sep string) string {
 
 // Rets describes function return parameters.
 type Rets struct {
-	Name         string
-	Type         string
-	ReturnsError bool
-	FailCond     string
+	Name          string
+	Type          string
+	ReturnsError  bool
+	FailCond      string
+	fnMaybeAbsent bool
 }
 
 // ErrorVarName returns error variable name for r.
@@ -252,6 +276,8 @@ func (r *Rets) List() string {
 	s := join(r.ToParams(), func(p *Param) string { return p.Name + " " + p.Type }, ", ")
 	if len(s) > 0 {
 		s = "(" + s + ")"
+	} else if r.fnMaybeAbsent {
+		s = "(err error)"
 	}
 	return s
 }
@@ -280,17 +306,13 @@ func (r *Rets) SetReturnValuesCode() string {
 
 func (r *Rets) useLongHandleErrorCode(retvar string) string {
 	const code = `if %s {
-		if e1 != 0 {
-			err = errnoErr(e1)
-		} else {
-			err = %sEINVAL
-		}
+		err = errnoErr(e1)
 	}`
 	cond := retvar + " == 0"
 	if r.FailCond != "" {
 		cond = strings.Replace(r.FailCond, "failretval", retvar, 1)
 	}
-	return fmt.Sprintf(code, cond, syscalldot())
+	return fmt.Sprintf(code, cond)
 }
 
 // SetErrorCode returns source code that sets return parameters.
@@ -455,6 +477,10 @@ func newFn(s string) (*Fn, error) {
 	default:
 		return nil, errors.New("Could not extract dll name from \"" + f.src + "\"")
 	}
+	if n := f.dllfuncname; strings.HasSuffix(n, "?") {
+		f.dllfuncname = n[:len(n)-1]
+		f.Rets.fnMaybeAbsent = true
+	}
 	return f, nil
 }
 
@@ -553,6 +579,22 @@ func (f *Fn) HelperCallParamList() string {
 	return strings.Join(a, ", ")
 }
 
+// MaybeAbsent returns source code for handling functions that are possibly unavailable.
+func (p *Fn) MaybeAbsent() string {
+	if !p.Rets.fnMaybeAbsent {
+		return ""
+	}
+	const code = `%[1]s = proc%[2]s.Find()
+	if %[1]s != nil {
+		return
+	}`
+	errorVar := p.Rets.ErrorVarName()
+	if errorVar == "" {
+		errorVar = "err"
+	}
+	return fmt.Sprintf(code, errorVar, p.DLLFuncName())
+}
+
 // IsUTF16 is true, if f is W (utf16) function. It is false
 // for all A (ascii) functions.
 func (f *Fn) IsUTF16() bool {
@@ -657,6 +699,7 @@ func (src *Source) DLLs() []string {
 			r = append(r, name)
 		}
 	}
+	sort.Strings(r)
 	return r
 }
 
@@ -691,6 +734,13 @@ func (src *Source) ParseFile(path string) error {
 		return err
 	}
 	src.Files = append(src.Files, path)
+	sort.Slice(src.Funcs, func(i, j int) bool {
+		fi, fj := src.Funcs[i], src.Funcs[j]
+		if fi.DLLName() == fj.DLLName() {
+			return fi.DLLFuncName() < fj.DLLFuncName()
+		}
+		return fi.DLLName() < fj.DLLName()
+	})
 
 	// get package name
 	fset := token.NewFileSet()
@@ -850,6 +900,7 @@ const (
 
 var (
 	errERROR_IO_PENDING error = {{syscalldot}}Errno(errnoERROR_IO_PENDING)
+	errERROR_EINVAL error     = {{syscalldot}}EINVAL
 )
 
 // errnoErr returns common boxed Errno values, to prevent
@@ -857,7 +908,7 @@ var (
 func errnoErr(e {{syscalldot}}Errno) error {
 	switch e {
 	case 0:
-		return nil
+		return errERROR_EINVAL
 	case errnoERROR_IO_PENDING:
 		return errERROR_IO_PENDING
 	}
@@ -889,7 +940,7 @@ func {{.Name}}({{.ParamList}}) {{template "results" .}}{
 
 {{define "funcbody"}}
 func {{.HelperName}}({{.HelperParamList}}) {{template "results" .}}{
-{{template "tmpvars" .}}	{{template "syscall" .}}
+{{template "maybeabsent" .}}	{{template "tmpvars" .}}	{{template "syscall" .}}	{{template "tmpvarsreadback" .}}
 {{template "seterror" .}}{{template "printtrace" .}}	return
 }
 {{end}}
@@ -897,6 +948,9 @@ func {{.HelperName}}({{.HelperParamList}}) {{template "results" .}}{
 {{define "helpertmpvars"}}{{range .Params}}{{if .TmpVarHelperCode}}	{{.TmpVarHelperCode}}
 {{end}}{{end}}{{end}}
 
+{{define "maybeabsent"}}{{if .MaybeAbsent}}{{.MaybeAbsent}}
+{{end}}{{end}}
+
 {{define "tmpvars"}}{{range .Params}}{{if .TmpVarCode}}	{{.TmpVarCode}}
 {{end}}{{end}}{{end}}
 
@@ -904,6 +958,9 @@ func {{.HelperName}}({{.HelperParamList}}) {{template "results" .}}{
 
 {{define "syscall"}}{{.Rets.SetReturnValuesCode}}{{.Syscall}}(proc{{.DLLFuncName}}.Addr(), {{.ParamCount}}, {{.SyscallParamList}}){{end}}
 
+{{define "tmpvarsreadback"}}{{range .Params}}{{if .TmpVarReadbackCode}}
+{{.TmpVarReadbackCode}}{{end}}{{end}}{{end}}
+
 {{define "seterror"}}{{if .Rets.SetErrorCode}}	{{.Rets.SetErrorCode}}
 {{end}}{{end}}
 

pkg/etw/zsyscall_windows.go

@@ -19,6 +19,7 @@ const (
 
 var (
 	errERROR_IO_PENDING error = syscall.Errno(errnoERROR_IO_PENDING)
+	errERROR_EINVAL     error = syscall.EINVAL
 )
 
 // errnoErr returns common boxed Errno values, to prevent
@@ -26,7 +27,7 @@ var (
 func errnoErr(e syscall.Errno) error {
 	switch e {
 	case 0:
-		return nil
+		return errERROR_EINVAL
 	case errnoERROR_IO_PENDING:
 		return errERROR_IO_PENDING
 	}
@@ -40,9 +41,9 @@ var (
 	modadvapi32 = windows.NewLazySystemDLL("advapi32.dll")
 
 	procEventRegister       = modadvapi32.NewProc("EventRegister")
+	procEventSetInformation = modadvapi32.NewProc("EventSetInformation")
 	procEventUnregister     = modadvapi32.NewProc("EventUnregister")
 	procEventWriteTransfer  = modadvapi32.NewProc("EventWriteTransfer")
-	procEventSetInformation = modadvapi32.NewProc("EventSetInformation")
 )
 
 func eventRegister(providerId *windows.GUID, callback uintptr, callbackContext uintptr, providerHandle *providerHandle) (win32err error) {
@@ -53,22 +54,6 @@ func eventRegister(providerId *windows.GUID, callback uintptr, callbackContext u
 	return
 }
 
-func eventUnregister_64(providerHandle providerHandle) (win32err error) {
-	r0, _, _ := syscall.Syscall(procEventUnregister.Addr(), 1, uintptr(providerHandle), 0, 0)
-	if r0 != 0 {
-		win32err = syscall.Errno(r0)
-	}
-	return
-}
-
-func eventWriteTransfer_64(providerHandle providerHandle, descriptor *eventDescriptor, activityID *windows.GUID, relatedActivityID *windows.GUID, dataDescriptorCount uint32, dataDescriptors *eventDataDescriptor) (win32err error) {
-	r0, _, _ := syscall.Syscall6(procEventWriteTransfer.Addr(), 6, uintptr(providerHandle), uintptr(unsafe.Pointer(descriptor)), uintptr(unsafe.Pointer(activityID)), uintptr(unsafe.Pointer(relatedActivityID)), uintptr(dataDescriptorCount), uintptr(unsafe.Pointer(dataDescriptors)))
-	if r0 != 0 {
-		win32err = syscall.Errno(r0)
-	}
-	return
-}
-
 func eventSetInformation_64(providerHandle providerHandle, class eventInfoClass, information uintptr, length uint32) (win32err error) {
 	r0, _, _ := syscall.Syscall6(procEventSetInformation.Addr(), 4, uintptr(providerHandle), uintptr(class), uintptr(information), uintptr(length), 0, 0)
 	if r0 != 0 {
@@ -77,6 +62,22 @@ func eventSetInformation_64(providerHandle providerHandle, class eventInfoClass,
 	return
 }
 
+func eventSetInformation_32(providerHandle_low uint32, providerHandle_high uint32, class eventInfoClass, information uintptr, length uint32) (win32err error) {
+	r0, _, _ := syscall.Syscall6(procEventSetInformation.Addr(), 5, uintptr(providerHandle_low), uintptr(providerHandle_high), uintptr(class), uintptr(information), uintptr(length), 0)
+	if r0 != 0 {
+		win32err = syscall.Errno(r0)
+	}
+	return
+}
+
+func eventUnregister_64(providerHandle providerHandle) (win32err error) {
+	r0, _, _ := syscall.Syscall(procEventUnregister.Addr(), 1, uintptr(providerHandle), 0, 0)
+	if r0 != 0 {
+		win32err = syscall.Errno(r0)
+	}
+	return
+}
+
 func eventUnregister_32(providerHandle_low uint32, providerHandle_high uint32) (win32err error) {
 	r0, _, _ := syscall.Syscall(procEventUnregister.Addr(), 2, uintptr(providerHandle_low), uintptr(providerHandle_high), 0)
 	if r0 != 0 {
@@ -85,6 +86,14 @@ func eventUnregister_32(providerHandle_low uint32, providerHandle_high uint32) (
 	return
 }
 
+func eventWriteTransfer_64(providerHandle providerHandle, descriptor *eventDescriptor, activityID *windows.GUID, relatedActivityID *windows.GUID, dataDescriptorCount uint32, dataDescriptors *eventDataDescriptor) (win32err error) {
+	r0, _, _ := syscall.Syscall6(procEventWriteTransfer.Addr(), 6, uintptr(providerHandle), uintptr(unsafe.Pointer(descriptor)), uintptr(unsafe.Pointer(activityID)), uintptr(unsafe.Pointer(relatedActivityID)), uintptr(dataDescriptorCount), uintptr(unsafe.Pointer(dataDescriptors)))
+	if r0 != 0 {
+		win32err = syscall.Errno(r0)
+	}
+	return
+}
+
 func eventWriteTransfer_32(providerHandle_low uint32, providerHandle_high uint32, descriptor *eventDescriptor, activityID *windows.GUID, relatedActivityID *windows.GUID, dataDescriptorCount uint32, dataDescriptors *eventDataDescriptor) (win32err error) {
 	r0, _, _ := syscall.Syscall9(procEventWriteTransfer.Addr(), 7, uintptr(providerHandle_low), uintptr(providerHandle_high), uintptr(unsafe.Pointer(descriptor)), uintptr(unsafe.Pointer(activityID)), uintptr(unsafe.Pointer(relatedActivityID)), uintptr(dataDescriptorCount), uintptr(unsafe.Pointer(dataDescriptors)), 0, 0)
 	if r0 != 0 {
@@ -92,11 +101,3 @@ func eventWriteTransfer_32(providerHandle_low uint32, providerHandle_high uint32
 	}
 	return
 }
-
-func eventSetInformation_32(providerHandle_low uint32, providerHandle_high uint32, class eventInfoClass, information uintptr, length uint32) (win32err error) {
-	r0, _, _ := syscall.Syscall6(procEventSetInformation.Addr(), 5, uintptr(providerHandle_low), uintptr(providerHandle_high), uintptr(class), uintptr(information), uintptr(length), 0)
-	if r0 != 0 {
-		win32err = syscall.Errno(r0)
-	}
-	return
-}