| // Copyright 2018 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 |
| |
| /* |
| This program reads a file containing function prototypes |
| (like syscall_darwin.go) and generates system call bodies. |
| 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 errno. |
| |
| A line beginning with //sysnb is like //sys, except that the |
| goroutine will not be suspended during the execution of the system |
| call. This must only be used for system calls which can never |
| block, as otherwise the system call could cause all goroutines to |
| hang. |
| */ |
| package main |
| |
| import ( |
| "bufio" |
| "flag" |
| "fmt" |
| "os" |
| "regexp" |
| "strings" |
| ) |
| |
| var ( |
| b32 = flag.Bool("b32", false, "32bit big-endian") |
| l32 = flag.Bool("l32", false, "32bit little-endian") |
| plan9 = flag.Bool("plan9", false, "plan9") |
| openbsd = flag.Bool("openbsd", false, "openbsd") |
| netbsd = flag.Bool("netbsd", false, "netbsd") |
| dragonfly = flag.Bool("dragonfly", false, "dragonfly") |
| arm = flag.Bool("arm", false, "arm") // 64-bit value should use (even, odd)-pair |
| tags = flag.String("tags", "", "build tags") |
| filename = flag.String("output", "", "output file name (standard output if omitted)") |
| ) |
| |
| // cmdLine returns this programs's commandline arguments |
| func cmdLine() string { |
| return "go run mksyscall.go " + strings.Join(os.Args[1:], " ") |
| } |
| |
| // buildTags returns build tags |
| func buildTags() string { |
| return *tags |
| } |
| |
| // Param is function parameter |
| type Param struct { |
| Name string |
| Type string |
| } |
| |
| // usage prints the program usage |
| func usage() { |
| fmt.Fprintf(os.Stderr, "usage: go run mksyscall.go [-b32 | -l32] [-tags x,y] [file ...]\n") |
| os.Exit(1) |
| } |
| |
| // parseParamList parses parameter list and returns a slice of parameters |
| func parseParamList(list string) []string { |
| list = strings.TrimSpace(list) |
| if list == "" { |
| return []string{} |
| } |
| return regexp.MustCompile(`\s*,\s*`).Split(list, -1) |
| } |
| |
| // parseParam splits a parameter into name and type |
| func parseParam(p string) Param { |
| ps := regexp.MustCompile(`^(\S*) (\S*)$`).FindStringSubmatch(p) |
| if ps == nil { |
| fmt.Fprintf(os.Stderr, "malformed parameter: %s\n", p) |
| os.Exit(1) |
| } |
| return Param{ps[1], ps[2]} |
| } |
| |
| func main() { |
| // Get the OS and architecture (using GOARCH_TARGET if it exists) |
| goos := os.Getenv("GOOS") |
| if goos == "" { |
| fmt.Fprintln(os.Stderr, "GOOS not defined in environment") |
| os.Exit(1) |
| } |
| goarch := os.Getenv("GOARCH_TARGET") |
| if goarch == "" { |
| goarch = os.Getenv("GOARCH") |
| } |
| |
| // Check that we are using the Docker-based build system if we should |
| if goos == "linux" { |
| if os.Getenv("GOLANG_SYS_BUILD") != "docker" { |
| fmt.Fprintf(os.Stderr, "In the Docker-based build system, mksyscall should not be called directly.\n") |
| fmt.Fprintf(os.Stderr, "See README.md\n") |
| os.Exit(1) |
| } |
| } |
| |
| flag.Usage = usage |
| flag.Parse() |
| if len(flag.Args()) <= 0 { |
| fmt.Fprintf(os.Stderr, "no files to parse provided\n") |
| usage() |
| } |
| |
| endianness := "" |
| if *b32 { |
| endianness = "big-endian" |
| } else if *l32 { |
| endianness = "little-endian" |
| } |
| |
| libc := false |
| if goos == "darwin" && (strings.Contains(buildTags(), ",go1.12") || strings.Contains(buildTags(), ",go1.13")) { |
| libc = true |
| } |
| trampolines := map[string]bool{} |
| |
| text := "" |
| for _, path := range flag.Args() { |
| file, err := os.Open(path) |
| if err != nil { |
| fmt.Fprintf(os.Stderr, err.Error()) |
| os.Exit(1) |
| } |
| s := bufio.NewScanner(file) |
| for s.Scan() { |
| t := s.Text() |
| t = strings.TrimSpace(t) |
| t = regexp.MustCompile(`\s+`).ReplaceAllString(t, ` `) |
| nonblock := regexp.MustCompile(`^\/\/sysnb `).FindStringSubmatch(t) |
| if regexp.MustCompile(`^\/\/sys `).FindStringSubmatch(t) == nil && nonblock == nil { |
| continue |
| } |
| |
| // Line must be of the form |
| // func Open(path string, mode int, perm int) (fd int, errno error) |
| // Split into name, in params, out params. |
| f := regexp.MustCompile(`^\/\/sys(nb)? (\w+)\(([^()]*)\)\s*(?:\(([^()]+)\))?\s*(?:=\s*((?i)SYS_[A-Z0-9_]+))?$`).FindStringSubmatch(t) |
| if f == nil { |
| fmt.Fprintf(os.Stderr, "%s:%s\nmalformed //sys declaration\n", path, t) |
| os.Exit(1) |
| } |
| funct, inps, outps, sysname := f[2], f[3], f[4], f[5] |
| |
| // ClockGettime doesn't have a syscall number on Darwin, only generate libc wrappers. |
| if goos == "darwin" && !libc && funct == "ClockGettime" { |
| continue |
| } |
| |
| // Split argument lists on comma. |
| in := parseParamList(inps) |
| out := parseParamList(outps) |
| |
| // Try in vain to keep people from editing this file. |
| // The theory is that they jump into the middle of the file |
| // without reading the header. |
| text += "// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT\n\n" |
| |
| // Go function header. |
| outDecl := "" |
| if len(out) > 0 { |
| outDecl = fmt.Sprintf(" (%s)", strings.Join(out, ", ")) |
| } |
| text += fmt.Sprintf("func %s(%s)%s {\n", funct, strings.Join(in, ", "), outDecl) |
| |
| // Check if err return available |
| errvar := "" |
| for _, param := range out { |
| p := parseParam(param) |
| if p.Type == "error" { |
| errvar = p.Name |
| break |
| } |
| } |
| |
| // Prepare arguments to Syscall. |
| var args []string |
| n := 0 |
| for _, param := range in { |
| p := parseParam(param) |
| if regexp.MustCompile(`^\*`).FindStringSubmatch(p.Type) != nil { |
| args = append(args, "uintptr(unsafe.Pointer("+p.Name+"))") |
| } else if p.Type == "string" && errvar != "" { |
| text += fmt.Sprintf("\tvar _p%d *byte\n", n) |
| text += fmt.Sprintf("\t_p%d, %s = BytePtrFromString(%s)\n", n, errvar, p.Name) |
| text += fmt.Sprintf("\tif %s != nil {\n\t\treturn\n\t}\n", errvar) |
| args = append(args, fmt.Sprintf("uintptr(unsafe.Pointer(_p%d))", n)) |
| n++ |
| } else if p.Type == "string" { |
| fmt.Fprintf(os.Stderr, path+":"+funct+" uses string arguments, but has no error return\n") |
| text += fmt.Sprintf("\tvar _p%d *byte\n", n) |
| text += fmt.Sprintf("\t_p%d, _ = BytePtrFromString(%s)\n", n, p.Name) |
| args = append(args, fmt.Sprintf("uintptr(unsafe.Pointer(_p%d))", n)) |
| n++ |
| } else if regexp.MustCompile(`^\[\](.*)`).FindStringSubmatch(p.Type) != nil { |
| // Convert slice into pointer, length. |
| // Have to be careful not to take address of &a[0] if len == 0: |
| // pass dummy pointer in that case. |
| // Used to pass nil, but some OSes or simulators reject write(fd, nil, 0). |
| text += fmt.Sprintf("\tvar _p%d unsafe.Pointer\n", n) |
| text += fmt.Sprintf("\tif len(%s) > 0 {\n\t\t_p%d = unsafe.Pointer(&%s[0])\n\t}", p.Name, n, p.Name) |
| text += fmt.Sprintf(" else {\n\t\t_p%d = unsafe.Pointer(&_zero)\n\t}\n", n) |
| args = append(args, fmt.Sprintf("uintptr(_p%d)", n), fmt.Sprintf("uintptr(len(%s))", p.Name)) |
| n++ |
| } else if p.Type == "int64" && (*openbsd || *netbsd) { |
| args = append(args, "0") |
| if endianness == "big-endian" { |
| args = append(args, fmt.Sprintf("uintptr(%s>>32)", p.Name), fmt.Sprintf("uintptr(%s)", p.Name)) |
| } else if endianness == "little-endian" { |
| args = append(args, fmt.Sprintf("uintptr(%s)", p.Name), fmt.Sprintf("uintptr(%s>>32)", p.Name)) |
| } else { |
| args = append(args, fmt.Sprintf("uintptr(%s)", p.Name)) |
| } |
| } else if p.Type == "int64" && *dragonfly { |
| if regexp.MustCompile(`^(?i)extp(read|write)`).FindStringSubmatch(funct) == nil { |
| args = append(args, "0") |
| } |
| if endianness == "big-endian" { |
| args = append(args, fmt.Sprintf("uintptr(%s>>32)", p.Name), fmt.Sprintf("uintptr(%s)", p.Name)) |
| } else if endianness == "little-endian" { |
| args = append(args, fmt.Sprintf("uintptr(%s)", p.Name), fmt.Sprintf("uintptr(%s>>32)", p.Name)) |
| } else { |
| args = append(args, fmt.Sprintf("uintptr(%s)", p.Name)) |
| } |
| } else if (p.Type == "int64" || p.Type == "uint64") && endianness != "" { |
| if len(args)%2 == 1 && *arm { |
| // arm abi specifies 64-bit argument uses |
| // (even, odd) pair |
| args = append(args, "0") |
| } |
| if endianness == "big-endian" { |
| args = append(args, fmt.Sprintf("uintptr(%s>>32)", p.Name), fmt.Sprintf("uintptr(%s)", p.Name)) |
| } else { |
| args = append(args, fmt.Sprintf("uintptr(%s)", p.Name), fmt.Sprintf("uintptr(%s>>32)", p.Name)) |
| } |
| } else { |
| args = append(args, fmt.Sprintf("uintptr(%s)", p.Name)) |
| } |
| } |
| |
| // Determine which form to use; pad args with zeros. |
| asm := "Syscall" |
| if nonblock != nil { |
| if errvar == "" && goos == "linux" { |
| asm = "RawSyscallNoError" |
| } else { |
| asm = "RawSyscall" |
| } |
| } else { |
| if errvar == "" && goos == "linux" { |
| asm = "SyscallNoError" |
| } |
| } |
| if len(args) <= 3 { |
| for len(args) < 3 { |
| args = append(args, "0") |
| } |
| } else if len(args) <= 6 { |
| asm += "6" |
| for len(args) < 6 { |
| args = append(args, "0") |
| } |
| } else if len(args) <= 9 { |
| asm += "9" |
| for len(args) < 9 { |
| args = append(args, "0") |
| } |
| } else { |
| fmt.Fprintf(os.Stderr, "%s:%s too many arguments to system call\n", path, funct) |
| } |
| |
| // System call number. |
| if sysname == "" { |
| sysname = "SYS_" + funct |
| sysname = regexp.MustCompile(`([a-z])([A-Z])`).ReplaceAllString(sysname, `${1}_$2`) |
| sysname = strings.ToUpper(sysname) |
| } |
| |
| var libcFn string |
| if libc { |
| asm = "syscall_" + strings.ToLower(asm[:1]) + asm[1:] // internal syscall call |
| sysname = strings.TrimPrefix(sysname, "SYS_") // remove SYS_ |
| sysname = strings.ToLower(sysname) // lowercase |
| libcFn = sysname |
| sysname = "funcPC(libc_" + sysname + "_trampoline)" |
| } |
| |
| // Actual call. |
| arglist := strings.Join(args, ", ") |
| call := fmt.Sprintf("%s(%s, %s)", asm, sysname, arglist) |
| |
| // Assign return values. |
| body := "" |
| ret := []string{"_", "_", "_"} |
| doErrno := false |
| for i := 0; i < len(out); i++ { |
| p := parseParam(out[i]) |
| reg := "" |
| if p.Name == "err" && !*plan9 { |
| reg = "e1" |
| ret[2] = reg |
| doErrno = true |
| } else if p.Name == "err" && *plan9 { |
| ret[0] = "r0" |
| ret[2] = "e1" |
| break |
| } else { |
| reg = fmt.Sprintf("r%d", i) |
| ret[i] = reg |
| } |
| if p.Type == "bool" { |
| reg = fmt.Sprintf("%s != 0", reg) |
| } |
| if p.Type == "int64" && endianness != "" { |
| // 64-bit number in r1:r0 or r0:r1. |
| if i+2 > len(out) { |
| fmt.Fprintf(os.Stderr, "%s:%s not enough registers for int64 return\n", path, funct) |
| } |
| if endianness == "big-endian" { |
| reg = fmt.Sprintf("int64(r%d)<<32 | int64(r%d)", i, i+1) |
| } else { |
| reg = fmt.Sprintf("int64(r%d)<<32 | int64(r%d)", i+1, i) |
| } |
| ret[i] = fmt.Sprintf("r%d", i) |
| ret[i+1] = fmt.Sprintf("r%d", i+1) |
| } |
| if reg != "e1" || *plan9 { |
| body += fmt.Sprintf("\t%s = %s(%s)\n", p.Name, p.Type, reg) |
| } |
| } |
| if ret[0] == "_" && ret[1] == "_" && ret[2] == "_" { |
| text += fmt.Sprintf("\t%s\n", call) |
| } else { |
| if errvar == "" && goos == "linux" { |
| // raw syscall without error on Linux, see golang.org/issue/22924 |
| text += fmt.Sprintf("\t%s, %s := %s\n", ret[0], ret[1], call) |
| } else { |
| text += fmt.Sprintf("\t%s, %s, %s := %s\n", ret[0], ret[1], ret[2], call) |
| } |
| } |
| text += body |
| |
| if *plan9 && ret[2] == "e1" { |
| text += "\tif int32(r0) == -1 {\n" |
| text += "\t\terr = e1\n" |
| text += "\t}\n" |
| } else if doErrno { |
| text += "\tif e1 != 0 {\n" |
| text += "\t\terr = errnoErr(e1)\n" |
| text += "\t}\n" |
| } |
| text += "\treturn\n" |
| text += "}\n\n" |
| |
| if libc && !trampolines[libcFn] { |
| // some system calls share a trampoline, like read and readlen. |
| trampolines[libcFn] = true |
| // Declare assembly trampoline. |
| text += fmt.Sprintf("func libc_%s_trampoline()\n", libcFn) |
| // Assembly trampoline calls the libc_* function, which this magic |
| // redirects to use the function from libSystem. |
| text += fmt.Sprintf("//go:linkname libc_%s libc_%s\n", libcFn, libcFn) |
| text += fmt.Sprintf("//go:cgo_import_dynamic libc_%s %s \"/usr/lib/libSystem.B.dylib\"\n", libcFn, libcFn) |
| text += "\n" |
| } |
| } |
| if err := s.Err(); err != nil { |
| fmt.Fprintf(os.Stderr, err.Error()) |
| os.Exit(1) |
| } |
| file.Close() |
| } |
| fmt.Printf(srcTemplate, cmdLine(), buildTags(), text) |
| } |
| |
| const srcTemplate = `// %s |
| // Code generated by the command above; see README.md. DO NOT EDIT. |
| |
| // +build %s |
| |
| package unix |
| |
| import ( |
| "syscall" |
| "unsafe" |
| ) |
| |
| var _ syscall.Errno |
| |
| %s |
| ` |
