// Copyright 2013 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. // +build ignore /* mksyscall_windows generates windows system call bodies It parses all files specified on command line containing function prototypes (like syscall_windows.go) and prints system call bodies to standard output. The prototypes are marked by lines beginning with "//sys" and read like func declarations if //sys is replaced by func, but: * The parameter lists must give a name for each argument. This includes return parameters. * The parameter lists must give a type for each argument: the (x, y, z int) shorthand is not allowed. * If the return parameter is an error number, it must be named err. * If go func name needs to be different from it's winapi dll name, the winapi name could be specified at the end, after "=" sign, like //sys LoadLibrary(libname string) (handle uint32, err error) = LoadLibraryA * Each function that returns err needs to supply a condition, that return value of winapi will be tested against to detect failure. This would set err to windows "last-error", otherwise it will be nil. The value can be provided at end of //sys declaration, like //sys LoadLibrary(libname string) (handle uint32, err error) [failretval==-1] = LoadLibraryA and is [failretval==0] by default. Usage: mksyscall_windows [flags] [path ...] The flags are: -output Specify output file name (outputs to console if blank). -trace Generate print statement after every syscall. */ package main import ( "bufio" "bytes" "errors" "flag" "fmt" "go/format" "go/parser" "go/token" "io" "io/ioutil" "log" "os" "path/filepath" "runtime" "sort" "strconv" "strings" "text/template" ) var ( filename = flag.String("output", "", "output file name (standard output if omitted)") printTraceFlag = flag.Bool("trace", false, "generate print statement after every syscall") systemDLL = flag.Bool("systemdll", true, "whether all DLLs should be loaded from the Windows system directory") ) func trim(s string) string { return strings.Trim(s, " \t") } var packageName string func packagename() string { return packageName } func syscalldot() string { if packageName == "syscall" { return "" } return "syscall." } // Param is function parameter type Param struct { Name string Type string fn *Fn tmpVarIdx int } // tmpVar returns temp variable name that will be used to represent p during syscall. func (p *Param) tmpVar() string { if p.tmpVarIdx < 0 { p.tmpVarIdx = p.fn.curTmpVarIdx p.fn.curTmpVarIdx++ } return fmt.Sprintf("_p%d", p.tmpVarIdx) } // 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 }` tmp := p.tmpVar() return fmt.Sprintf(code, tmp, p.Name, tmp, tmp) } // SliceTmpVarCode returns source code for slice temp variable. func (p *Param) SliceTmpVarCode() string { const code = `var %s *%s if len(%s) > 0 { %s = &%s[0] }` tmp := p.tmpVar() return fmt.Sprintf(code, tmp, p.Type[2:], p.Name, tmp, p.Name) } // StringTmpVarCode returns source code for string temp variable. func (p *Param) StringTmpVarCode() string { errvar := p.fn.Rets.ErrorVarName() if errvar == "" { errvar = "_" } tmp := p.tmpVar() const code = `var %s %s %s, %s = %s(%s)` s := fmt.Sprintf(code, tmp, p.fn.StrconvType(), tmp, errvar, p.fn.StrconvFunc(), p.Name) if errvar == "-" { return s } const morecode = ` if %s != nil { return }` return s + fmt.Sprintf(morecode, errvar) } // TmpVarCode returns source code for temp variable. func (p *Param) TmpVarCode() string { switch { case p.Type == "bool": return p.BoolTmpVarCode() case strings.HasPrefix(p.Type, "[]"): return p.SliceTmpVarCode() default: return "" } } // TmpVarHelperCode returns source code for helper's temp variable. func (p *Param) TmpVarHelperCode() string { if p.Type != "string" { return "" } return p.StringTmpVarCode() } // SyscallArgList returns source code fragments representing p parameter // in syscall. Slices are translated into 2 syscall parameters: pointer to // the first element and length. func (p *Param) SyscallArgList() []string { t := p.HelperType() var s string switch { case t[0] == '*': s = fmt.Sprintf("unsafe.Pointer(%s)", p.Name) case t == "bool": s = p.tmpVar() case strings.HasPrefix(t, "[]"): return []string{ fmt.Sprintf("uintptr(unsafe.Pointer(%s))", p.tmpVar()), fmt.Sprintf("uintptr(len(%s))", p.Name), } default: s = p.Name } return []string{fmt.Sprintf("uintptr(%s)", s)} } // IsError determines if p parameter is used to return error. func (p *Param) IsError() bool { return p.Name == "err" && p.Type == "error" } // HelperType returns type of parameter p used in helper function. func (p *Param) HelperType() string { if p.Type == "string" { return p.fn.StrconvType() } return p.Type } // join concatenates parameters ps into a string with sep separator. // Each parameter is converted into string by applying fn to it // before conversion. func join(ps []*Param, fn func(*Param) string, sep string) string { if len(ps) == 0 { return "" } a := make([]string, 0) for _, p := range ps { a = append(a, fn(p)) } return strings.Join(a, sep) } // Rets describes function return parameters. type Rets struct { Name string Type string ReturnsError bool FailCond string } // ErrorVarName returns error variable name for r. func (r *Rets) ErrorVarName() string { if r.ReturnsError { return "err" } if r.Type == "error" { return r.Name } return "" } // ToParams converts r into slice of *Param. func (r *Rets) ToParams() []*Param { ps := make([]*Param, 0) if len(r.Name) > 0 { ps = append(ps, &Param{Name: r.Name, Type: r.Type}) } if r.ReturnsError { ps = append(ps, &Param{Name: "err", Type: "error"}) } return ps } // List returns source code of syscall return parameters. func (r *Rets) List() string { s := join(r.ToParams(), func(p *Param) string { return p.Name + " " + p.Type }, ", ") if len(s) > 0 { s = "(" + s + ")" } return s } // PrintList returns source code of trace printing part correspondent // to syscall return values. func (r *Rets) PrintList() string { return join(r.ToParams(), func(p *Param) string { return fmt.Sprintf(`"%s=", %s, `, p.Name, p.Name) }, `", ", `) } // SetReturnValuesCode returns source code that accepts syscall return values. func (r *Rets) SetReturnValuesCode() string { if r.Name == "" && !r.ReturnsError { return "" } retvar := "r0" if r.Name == "" { retvar = "r1" } errvar := "_" if r.ReturnsError { errvar = "e1" } return fmt.Sprintf("%s, _, %s := ", retvar, errvar) } func (r *Rets) useLongHandleErrorCode(retvar string) string { const code = `if %s { if e1 != 0 { err = errnoErr(e1) } else { err = %sEINVAL } }` cond := retvar + " == 0" if r.FailCond != "" { cond = strings.Replace(r.FailCond, "failretval", retvar, 1) } return fmt.Sprintf(code, cond, syscalldot()) } // SetErrorCode returns source code that sets return parameters. func (r *Rets) SetErrorCode() string { const code = `if r0 != 0 { %s = %sErrno(r0) }` const hrCode = `if int32(r0) < 0 { %s = %sErrno(win32FromHresult(r0)) }` if r.Name == "" && !r.ReturnsError { return "" } if r.Name == "" { return r.useLongHandleErrorCode("r1") } if r.Type == "error" { if r.Name == "hr" { return fmt.Sprintf(hrCode, r.Name, syscalldot()) } else { return fmt.Sprintf(code, r.Name, syscalldot()) } } s := "" switch { case r.Type[0] == '*': s = fmt.Sprintf("%s = (%s)(unsafe.Pointer(r0))", r.Name, r.Type) case r.Type == "bool": s = fmt.Sprintf("%s = r0 != 0", r.Name) default: s = fmt.Sprintf("%s = %s(r0)", r.Name, r.Type) } if !r.ReturnsError { return s } return s + "\n\t" + r.useLongHandleErrorCode(r.Name) } // Fn describes syscall function. type Fn struct { Name string Params []*Param Rets *Rets PrintTrace bool confirmproc bool dllname string dllfuncname string src string // TODO: get rid of this field and just use parameter index instead curTmpVarIdx int // insure tmp variables have uniq names } // extractParams parses s to extract function parameters. func extractParams(s string, f *Fn) ([]*Param, error) { s = trim(s) if s == "" { return nil, nil } a := strings.Split(s, ",") ps := make([]*Param, len(a)) for i := range ps { s2 := trim(a[i]) b := strings.Split(s2, " ") if len(b) != 2 { b = strings.Split(s2, "\t") if len(b) != 2 { return nil, errors.New("Could not extract function parameter from \"" + s2 + "\"") } } ps[i] = &Param{ Name: trim(b[0]), Type: trim(b[1]), fn: f, tmpVarIdx: -1, } } return ps, nil } // extractSection extracts text out of string s starting after start // and ending just before end. found return value will indicate success, // and prefix, body and suffix will contain correspondent parts of string s. func extractSection(s string, start, end rune) (prefix, body, suffix string, found bool) { s = trim(s) if strings.HasPrefix(s, string(start)) { // no prefix body = s[1:] } else { a := strings.SplitN(s, string(start), 2) if len(a) != 2 { return "", "", s, false } prefix = a[0] body = a[1] } a := strings.SplitN(body, string(end), 2) if len(a) != 2 { return "", "", "", false } return prefix, a[0], a[1], true } // newFn parses string s and return created function Fn. func newFn(s string) (*Fn, error) { s = trim(s) f := &Fn{ Rets: &Rets{}, src: s, PrintTrace: *printTraceFlag, } // function name and args prefix, body, s, found := extractSection(s, '(', ')') if !found || prefix == "" { return nil, errors.New("Could not extract function name and parameters from \"" + f.src + "\"") } f.Name = prefix var err error f.Params, err = extractParams(body, f) if err != nil { return nil, err } // return values _, body, s, found = extractSection(s, '(', ')') if found { r, err := extractParams(body, f) if err != nil { return nil, err } switch len(r) { case 0: case 1: if r[0].IsError() { f.Rets.ReturnsError = true } else { f.Rets.Name = r[0].Name f.Rets.Type = r[0].Type } case 2: if !r[1].IsError() { return nil, errors.New("Only last windows error is allowed as second return value in \"" + f.src + "\"") } f.Rets.ReturnsError = true f.Rets.Name = r[0].Name f.Rets.Type = r[0].Type default: return nil, errors.New("Too many return values in \"" + f.src + "\"") } } // fail condition _, body, s, found = extractSection(s, '[', ']') if found { f.Rets.FailCond = body } // dll and dll function names s = trim(s) if s == "" { return f, nil } if !strings.HasPrefix(s, "=") { return nil, errors.New("Could not extract dll name from \"" + f.src + "\"") } s = trim(s[1:]) a := strings.Split(s, ".") switch len(a) { case 1: f.dllfuncname = a[0] case 2: f.dllname = a[0] f.dllfuncname = a[1] default: return nil, errors.New("Could not extract dll name from \"" + f.src + "\"") } if f.dllfuncname[len(f.dllfuncname)-1] == '?' { f.confirmproc = true f.dllfuncname = f.dllfuncname[0 : len(f.dllfuncname)-1] } return f, nil } // DLLName returns DLL name for function f. func (f *Fn) DLLName() string { if f.dllname == "" { return "kernel32" } return f.dllname } // DLLName returns DLL function name for function f. func (f *Fn) DLLFuncName() string { if f.dllfuncname == "" { return f.Name } return f.dllfuncname } func (f *Fn) ConfirmProc() bool { return f.confirmproc } // ParamList returns source code for function f parameters. func (f *Fn) ParamList() string { return join(f.Params, func(p *Param) string { return p.Name + " " + p.Type }, ", ") } // HelperParamList returns source code for helper function f parameters. func (f *Fn) HelperParamList() string { return join(f.Params, func(p *Param) string { return p.Name + " " + p.HelperType() }, ", ") } // ParamPrintList returns source code of trace printing part correspondent // to syscall input parameters. func (f *Fn) ParamPrintList() string { return join(f.Params, func(p *Param) string { return fmt.Sprintf(`"%s=", %s, `, p.Name, p.Name) }, `", ", `) } // ParamCount return number of syscall parameters for function f. func (f *Fn) ParamCount() int { n := 0 for _, p := range f.Params { n += len(p.SyscallArgList()) } return n } // SyscallParamCount determines which version of Syscall/Syscall6/Syscall9/... // to use. It returns parameter count for correspondent SyscallX function. func (f *Fn) SyscallParamCount() int { n := f.ParamCount() switch { case n <= 3: return 3 case n <= 6: return 6 case n <= 9: return 9 case n <= 12: return 12 case n <= 15: return 15 default: panic("too many arguments to system call") } } // Syscall determines which SyscallX function to use for function f. func (f *Fn) Syscall() string { c := f.SyscallParamCount() if c == 3 { return syscalldot() + "Syscall" } return syscalldot() + "Syscall" + strconv.Itoa(c) } // SyscallParamList returns source code for SyscallX parameters for function f. func (f *Fn) SyscallParamList() string { a := make([]string, 0) for _, p := range f.Params { a = append(a, p.SyscallArgList()...) } for len(a) < f.SyscallParamCount() { a = append(a, "0") } return strings.Join(a, ", ") } // HelperCallParamList returns source code of call into function f helper. func (f *Fn) HelperCallParamList() string { a := make([]string, 0, len(f.Params)) for _, p := range f.Params { s := p.Name if p.Type == "string" { s = p.tmpVar() } a = append(a, s) } return strings.Join(a, ", ") } // IsUTF16 is true, if f is W (utf16) function. It is false // for all A (ascii) functions. func (_ *Fn) IsUTF16() bool { return true } // StrconvFunc returns name of Go string to OS string function for f. func (f *Fn) StrconvFunc() string { if f.IsUTF16() { return syscalldot() + "UTF16PtrFromString" } return syscalldot() + "BytePtrFromString" } // StrconvType returns Go type name used for OS string for f. func (f *Fn) StrconvType() string { if f.IsUTF16() { return "*uint16" } return "*byte" } // HasStringParam is true, if f has at least one string parameter. // Otherwise it is false. func (f *Fn) HasStringParam() bool { for _, p := range f.Params { if p.Type == "string" { return true } } return false } var uniqDllFuncName = make(map[string]bool) // IsNotDuplicate is true if f is not a duplicated function func (f *Fn) IsNotDuplicate() bool { funcName := f.DLLFuncName() if uniqDllFuncName[funcName] == false { uniqDllFuncName[funcName] = true return true } return false } // HelperName returns name of function f helper. func (f *Fn) HelperName() string { if !f.HasStringParam() { return f.Name } return "_" + f.Name } // Source files and functions. type Source struct { Funcs []*Fn Files []string StdLibImports []string ExternalImports []string } func (src *Source) Import(pkg string) { src.StdLibImports = append(src.StdLibImports, pkg) sort.Strings(src.StdLibImports) } func (src *Source) ExternalImport(pkg string) { src.ExternalImports = append(src.ExternalImports, pkg) sort.Strings(src.ExternalImports) } // ParseFiles parses files listed in fs and extracts all syscall // functions listed in sys comments. It returns source files // and functions collection *Source if successful. func ParseFiles(fs []string) (*Source, error) { src := &Source{ Funcs: make([]*Fn, 0), Files: make([]string, 0), StdLibImports: []string{ "unsafe", }, ExternalImports: make([]string, 0), } for _, file := range fs { if err := src.ParseFile(file); err != nil { return nil, err } } return src, nil } // DLLs return dll names for a source set src. func (src *Source) DLLs() []string { uniq := make(map[string]bool) r := make([]string, 0) for _, f := range src.Funcs { name := f.DLLName() if _, found := uniq[name]; !found { uniq[name] = true r = append(r, name) } } return r } // ParseFile adds additional file path to a source set src. func (src *Source) ParseFile(path string) error { file, err := os.Open(path) if err != nil { return err } defer file.Close() s := bufio.NewScanner(file) for s.Scan() { t := trim(s.Text()) if len(t) < 7 { continue } if !strings.HasPrefix(t, "//sys") { continue } t = t[5:] if !(t[0] == ' ' || t[0] == '\t') { continue } f, err := newFn(t[1:]) if err != nil { return err } src.Funcs = append(src.Funcs, f) } if err := s.Err(); err != nil { return err } src.Files = append(src.Files, path) // get package name fset := token.NewFileSet() _, err = file.Seek(0, 0) if err != nil { return err } pkg, err := parser.ParseFile(fset, "", file, parser.PackageClauseOnly) if err != nil { return err } packageName = pkg.Name.Name return nil } // IsStdRepo returns true if src is part of standard library. func (src *Source) IsStdRepo() (bool, error) { if len(src.Files) == 0 { return false, errors.New("no input files provided") } abspath, err := filepath.Abs(src.Files[0]) if err != nil { return false, err } goroot := runtime.GOROOT() if runtime.GOOS == "windows" { abspath = strings.ToLower(abspath) goroot = strings.ToLower(goroot) } sep := string(os.PathSeparator) if !strings.HasSuffix(goroot, sep) { goroot += sep } return strings.HasPrefix(abspath, goroot), nil } // Generate output source file from a source set src. func (src *Source) Generate(w io.Writer) error { const ( pkgStd = iota // any package in std library pkgXSysWindows // x/sys/windows package pkgOther ) isStdRepo, err := src.IsStdRepo() if err != nil { return err } var pkgtype int switch { case isStdRepo: pkgtype = pkgStd case packageName == "windows": // TODO: this needs better logic than just using package name pkgtype = pkgXSysWindows default: pkgtype = pkgOther } if *systemDLL { switch pkgtype { case pkgStd: src.Import("internal/syscall/windows/sysdll") case pkgXSysWindows: default: src.ExternalImport("golang.org/x/sys/windows") } } src.ExternalImport("github.com/Microsoft/go-winio") if packageName != "syscall" { src.Import("syscall") } funcMap := template.FuncMap{ "packagename": packagename, "syscalldot": syscalldot, "newlazydll": func(dll string) string { arg := "\"" + dll + ".dll\"" if !*systemDLL { return syscalldot() + "NewLazyDLL(" + arg + ")" } switch pkgtype { case pkgStd: return syscalldot() + "NewLazyDLL(sysdll.Add(" + arg + "))" case pkgXSysWindows: return "NewLazySystemDLL(" + arg + ")" default: return "windows.NewLazySystemDLL(" + arg + ")" } }, } t := template.Must(template.New("main").Funcs(funcMap).Parse(srcTemplate)) err = t.Execute(w, src) if err != nil { return errors.New("Failed to execute template: " + err.Error()) } return nil } func usage() { fmt.Fprintf(os.Stderr, "usage: mksyscall_windows [flags] [path ...]\n") flag.PrintDefaults() os.Exit(1) } func main() { flag.Usage = usage flag.Parse() if len(flag.Args()) <= 0 { fmt.Fprintf(os.Stderr, "no files to parse provided\n") usage() } src, err := ParseFiles(flag.Args()) if err != nil { log.Fatal(err) } var buf bytes.Buffer if err := src.Generate(&buf); err != nil { log.Fatal(err) } data, err := format.Source(buf.Bytes()) if err != nil { log.Fatal(err) } if *filename == "" { _, err = os.Stdout.Write(data) } else { err = ioutil.WriteFile(*filename, data, 0644) } if err != nil { log.Fatal(err) } } // TODO: use println instead to print in the following template const srcTemplate = ` {{define "main"}}// MACHINE GENERATED BY 'go generate' COMMAND; DO NOT EDIT package {{packagename}} import ( {{range .StdLibImports}}"{{.}}" {{end}} {{range .ExternalImports}}"{{.}}" {{end}} ) var _ unsafe.Pointer // Do the interface allocations only once for common // Errno values. const ( errnoERROR_IO_PENDING = 997 ) var ( errERROR_IO_PENDING error = {{syscalldot}}Errno(errnoERROR_IO_PENDING) ) // errnoErr returns common boxed Errno values, to prevent // allocations at runtime. func errnoErr(e {{syscalldot}}Errno) error { switch e { case 0: return nil case errnoERROR_IO_PENDING: return errERROR_IO_PENDING } // TODO: add more here, after collecting data on the common // error values see on Windows. (perhaps when running // all.bat?) return e } var ( {{template "dlls" .}} {{template "funcnames" .}}) {{range .Funcs}}{{if .HasStringParam}}{{template "helperbody" .}}{{end}}{{template "funcbody" .}}{{end}} {{end}} {{/* help functions */}} {{define "dlls"}}{{range .DLLs}} mod{{.}} = {{newlazydll .}} {{end}}{{end}} {{define "funcnames"}}{{range .Funcs}}{{if .IsNotDuplicate}} proc{{.DLLFuncName}} = mod{{.DLLName}}.NewProc("{{.DLLFuncName}}"){{end}} {{end}}{{end}} {{define "helperbody"}} func {{.Name}}({{.ParamList}}) {{template "results" .}}{ {{template "helpertmpvars" .}} return {{.HelperName}}({{.HelperCallParamList}}) } {{end}} {{define "funcbody"}} func {{.HelperName}}({{.HelperParamList}}) {{template "results" .}}{ {{template "tmpvars" .}} {{template "syscallcheck" .}}{{template "syscall" .}} {{template "seterror" .}}{{template "printtrace" .}} return } {{end}} {{define "helpertmpvars"}}{{range .Params}}{{if .TmpVarHelperCode}} {{.TmpVarHelperCode}} {{end}}{{end}}{{end}} {{define "tmpvars"}}{{range .Params}}{{if .TmpVarCode}} {{.TmpVarCode}} {{end}}{{end}}{{end}} {{define "results"}}{{if .Rets.List}}{{.Rets.List}} {{end}}{{end}} {{define "syscall"}}{{.Rets.SetReturnValuesCode}}{{.Syscall}}(proc{{.DLLFuncName}}.Addr(), {{.ParamCount}}, {{.SyscallParamList}}){{end}} {{define "syscallcheck"}}{{if .ConfirmProc}}if {{.Rets.ErrorVarName}} = proc{{.DLLFuncName}}.Find(); {{.Rets.ErrorVarName}} != nil { return } {{end}}{{end}} {{define "seterror"}}{{if .Rets.SetErrorCode}} {{.Rets.SetErrorCode}} {{end}}{{end}} {{define "printtrace"}}{{if .PrintTrace}} print("SYSCALL: {{.Name}}(", {{.ParamPrintList}}") (", {{.Rets.PrintList}}")\n") {{end}}{{end}} `