--- /dev/null
+// 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() {
+ goos := os.Getenv("GOOS_TARGET")
+ if goos == "" {
+ goos = os.Getenv("GOOS")
+ }
+ if goos == "" {
+ fmt.Fprintln(os.Stderr, "GOOS not defined in environment")
+ os.Exit(1)
+ }
+
+ // 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" {
+ 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]
+
+ // 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: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
+`
projects / dotfiles / .git / blobdiff