unix/mksyscall_solaris.go - sys - Git at Google

 // Copyright 2019 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.

 //go:build ignore

 /*
  This program reads a file containing function prototypes
  (like syscall_solaris.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 err.
 	* If go func name needs to be different than its libc name,
 	* or the function is not in libc, name could be specified
 	* at the end, after "=" sign, like
 	  //sys	getsockopt(s int, level int, name int, val uintptr, vallen *_Socklen) (err error) = libsocket.getsockopt
 */

 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")
 	tags    = flag.String("tags", "", "build tags")
 	illumos = flag.Bool("illumos", false, "illumos specific code generation")
 )

 // cmdLine returns this programs's commandline arguments
 func cmdLine() string {
 	return "go run mksyscall_solaris.go " + strings.Join(os.Args[1:], " ")
 }

 // goBuildTags returns build tags in the go:build format.
 func goBuildTags() string {
 	return strings.ReplaceAll(*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_solaris.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() {
 	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"
 	}

 	pack := ""
 	text := ""
 	dynimports := ""
 	linknames := ""
 	var vars []string
 	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()
 			if p := regexp.MustCompile(`^package (\S+)$`).FindStringSubmatch(t); p != nil && pack == "" {
 				pack = p[1]
 			}
 			nonblock := regexp.MustCompile(`^\/\/sysnb\t`).FindStringSubmatch(t)
 			if regexp.MustCompile(`^\/\/sys\t`).FindStringSubmatch(t) == nil && nonblock == nil {
 				continue
 			}

 			// Line must be of the form
 			//	func Open(path string, mode int, perm int) (fd int, err error)
 			// Split into name, in params, out params.
 			f := regexp.MustCompile(`^\/\/sys(nb)?\t(\w+)\(([^()]*)\)\s*(?:\(([^()]+)\))?\s*(?:=\s*(?:(\w*)\.)?(\w*))?$`).FindStringSubmatch(t)
 			if f == nil {
 				fmt.Fprintf(os.Stderr, "%s:%s\nmalformed //sys declaration\n", path, t)
 				os.Exit(1)
 			}
 			funct, inps, outps, modname, sysname := f[2], f[3], f[4], f[5], f[6]

 			// Split argument lists on comma.
 			in := parseParamList(inps)
 			out := parseParamList(outps)

 			inps = strings.Join(in, ", ")
 			outps = strings.Join(out, ", ")

 			// 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"

 			// So file name.
 			if modname == "" {
 				modname = "libc"
 			}

 			// System call name.
 			if sysname == "" {
 				sysname = funct
 			}

 			// System call pointer variable name.
 			sysvarname := fmt.Sprintf("proc%s", sysname)

 			strconvfunc := "BytePtrFromString"
 			strconvtype := "*byte"

 			sysname = strings.ToLower(sysname) // All libc functions are lowercase.

 			if funct != "ioctlPtrRet" {
 				// Runtime import of function to allow cross-platform builds.
 				dynimports += fmt.Sprintf("//go:cgo_import_dynamic libc_%s %s \"%s.so\"\n", sysname, sysname, modname)
 				// Link symbol to proc address variable.
 				linknames += fmt.Sprintf("//go:linkname %s libc_%s\n", sysvarname, sysname)
 				// Library proc address variable.
 				vars = append(vars, sysvarname)
 			}

 			// Go function header.
 			outlist := strings.Join(out, ", ")
 			if outlist != "" {
 				outlist = fmt.Sprintf(" (%s)", outlist)
 			}
 			if text != "" {
 				text += "\n"
 			}
 			text += fmt.Sprintf("func %s(%s)%s {\n", funct, strings.Join(in, ", "), outlist)

 			// Check if err return available
 			errvar := ""
 			for _, param := range out {
 				p := parseParam(param)
 				if p.Type == "error" {
 					errvar = p.Name
 					continue
 				}
 			}

 			// 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 %s\n", n, strconvtype)
 					text += fmt.Sprintf("\t_p%d, %s = %s(%s)\n", n, errvar, strconvfunc, 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 %s\n", n, strconvtype)
 					text += fmt.Sprintf("\t_p%d, _ = %s(%s)\n", n, strconvfunc, p.Name)
 					args = append(args, fmt.Sprintf("uintptr(unsafe.Pointer(_p%d))", n))
 					n++
 				} else if s := regexp.MustCompile(`^\[\](.*)`).FindStringSubmatch(p.Type); s != nil {
 					// Convert slice into pointer, length.
 					// Have to be careful not to take address of &a[0] if len == 0:
 					// pass nil in that case.
 					text += fmt.Sprintf("\tvar _p%d *%s\n", n, s[1])
 					text += fmt.Sprintf("\tif len(%s) > 0 {\n\t\t_p%d = &%s[0]\n\t}\n", p.Name, n, p.Name)
 					args = append(args, fmt.Sprintf("uintptr(unsafe.Pointer(_p%d))", n), fmt.Sprintf("uintptr(len(%s))", p.Name))
 					n++
 				} else if p.Type == "int64" && endianness != "" {
 					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 if p.Type == "bool" {
 					text += fmt.Sprintf("\tvar _p%d uint32\n", n)
 					text += fmt.Sprintf("\tif %s {\n\t\t_p%d = 1\n\t} else {\n\t\t_p%d = 0\n\t}\n", p.Name, n, n)
 					args = append(args, fmt.Sprintf("uintptr(_p%d)", n))
 					n++
 				} else {
 					args = append(args, fmt.Sprintf("uintptr(%s)", p.Name))
 				}
 			}
 			nargs := len(args)

 			// Determine which form to use; pad args with zeros.
 			asm := "sysvicall6"
 			if nonblock != nil {
 				asm = "rawSysvicall6"
 			}
 			if len(args) <= 6 {
 				for len(args) < 6 {
 					args = append(args, "0")
 				}
 			} else {
 				fmt.Fprintf(os.Stderr, "%s: too many arguments to system call\n", path)
 				os.Exit(1)
 			}

 			// Actual call.
 			arglist := strings.Join(args, ", ")
 			call := fmt.Sprintf("%s(uintptr(unsafe.Pointer(&%s)), %d, %s)", asm, sysvarname, nargs, 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" {
 					reg = "e1"
 					ret[2] = reg
 					doErrno = true
 				} else {
 					reg = fmt.Sprintf("r%d", i)
 					ret[i] = reg
 				}
 				if p.Type == "bool" {
 					reg = fmt.Sprintf("%d != 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: not enough registers for int64 return\n", path)
 						os.Exit(1)
 					}
 					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" {
 					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 {
 				text += fmt.Sprintf("\t%s, %s, %s := %s\n", ret[0], ret[1], ret[2], call)
 			}
 			text += body

 			if doErrno {
 				text += "\tif e1 != 0 {\n"
 				text += "\t\terr = errnoErr(e1)\n"
 				text += "\t}\n"
 			}
 			text += "\treturn\n"
 			text += "}\n"
 		}
 		if err := s.Err(); err != nil {
 			fmt.Fprintf(os.Stderr, err.Error())
 			os.Exit(1)
 		}
 		file.Close()
 	}
 	imp := ""
 	if pack != "unix" {
 		imp = "import \"golang.org/x/sys/unix\"\n"
 	}

 	syscallimp := ""
 	if !*illumos {
 		syscallimp = "\"syscall\""
 	}

 	vardecls := "\t" + strings.Join(vars, ",\n\t")
 	vardecls += " syscallFunc"
 	fmt.Printf(srcTemplate, cmdLine(), goBuildTags(), pack, syscallimp, imp, dynimports, linknames, vardecls, text)
 }

 const srcTemplate = `// %s
 // Code generated by the command above; see README.md. DO NOT EDIT.

 //go:build %s

 package %s

 import (
         "unsafe"
         %s
 )
 %s
 %s
 %s
 var (
 %s
 )

 %s
 `
	// Copyright 2019 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.

	//go:build ignore

	/*
	This program reads a file containing function prototypes
	(like syscall_solaris.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 err.
	* If go func name needs to be different than its libc name,
	* or the function is not in libc, name could be specified
	* at the end, after "=" sign, like
	//sys getsockopt(s int, level int, name int, val uintptr, vallen *_Socklen) (err error) = libsocket.getsockopt
	*/

	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")
	tags = flag.String("tags", "", "build tags")
	illumos = flag.Bool("illumos", false, "illumos specific code generation")
	)

	// cmdLine returns this programs's commandline arguments
	func cmdLine() string {
	return "go run mksyscall_solaris.go " + strings.Join(os.Args[1:], " ")
	}

	// goBuildTags returns build tags in the go:build format.
	func goBuildTags() string {
	return strings.ReplaceAll(*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_solaris.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() {
	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"
	}

	pack := ""
	text := ""
	dynimports := ""
	linknames := ""
	var vars []string
	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()
	if p := regexp.MustCompile(`^package (\S+)$`).FindStringSubmatch(t); p != nil && pack == "" {
	pack = p[1]
	}
	nonblock := regexp.MustCompile(`^\/\/sysnb\t`).FindStringSubmatch(t)
	if regexp.MustCompile(`^\/\/sys\t`).FindStringSubmatch(t) == nil && nonblock == nil {
	continue
	}

	// Line must be of the form
	// func Open(path string, mode int, perm int) (fd int, err error)
	// Split into name, in params, out params.
	f := regexp.MustCompile(`^\/\/sys(nb)?\t(\w+)\(([^()])\)\s(?:\(([^()]+)\))?\s(?:=\s(?:(\w)\.)?(\w))?$`).FindStringSubmatch(t)
	if f == nil {
	fmt.Fprintf(os.Stderr, "%s:%s\nmalformed //sys declaration\n", path, t)
	os.Exit(1)
	}
	funct, inps, outps, modname, sysname := f[2], f[3], f[4], f[5], f[6]

	// Split argument lists on comma.
	in := parseParamList(inps)
	out := parseParamList(outps)

	inps = strings.Join(in, ", ")
	outps = strings.Join(out, ", ")

	// 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"

	// So file name.
	if modname == "" {
	modname = "libc"
	}

	// System call name.
	if sysname == "" {
	sysname = funct
	}

	// System call pointer variable name.
	sysvarname := fmt.Sprintf("proc%s", sysname)

	strconvfunc := "BytePtrFromString"
	strconvtype := "*byte"

	sysname = strings.ToLower(sysname) // All libc functions are lowercase.

	if funct != "ioctlPtrRet" {
	// Runtime import of function to allow cross-platform builds.
	dynimports += fmt.Sprintf("//go:cgo_import_dynamic libc_%s %s \"%s.so\"\n", sysname, sysname, modname)
	// Link symbol to proc address variable.
	linknames += fmt.Sprintf("//go:linkname %s libc_%s\n", sysvarname, sysname)
	// Library proc address variable.
	vars = append(vars, sysvarname)
	}

	// Go function header.
	outlist := strings.Join(out, ", ")
	if outlist != "" {
	outlist = fmt.Sprintf(" (%s)", outlist)
	}
	if text != "" {
	text += "\n"
	}
	text += fmt.Sprintf("func %s(%s)%s {\n", funct, strings.Join(in, ", "), outlist)

	// Check if err return available
	errvar := ""
	for _, param := range out {
	p := parseParam(param)
	if p.Type == "error" {
	errvar = p.Name
	continue
	}
	}

	// 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 %s\n", n, strconvtype)
	text += fmt.Sprintf("\t_p%d, %s = %s(%s)\n", n, errvar, strconvfunc, 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 %s\n", n, strconvtype)
	text += fmt.Sprintf("\t_p%d, _ = %s(%s)\n", n, strconvfunc, p.Name)
	args = append(args, fmt.Sprintf("uintptr(unsafe.Pointer(_p%d))", n))
	n++
	} else if s := regexp.MustCompile(`^\[\](.*)`).FindStringSubmatch(p.Type); s != nil {
	// Convert slice into pointer, length.
	// Have to be careful not to take address of &a[0] if len == 0:
	// pass nil in that case.
	text += fmt.Sprintf("\tvar _p%d *%s\n", n, s[1])
	text += fmt.Sprintf("\tif len(%s) > 0 {\n\t\t_p%d = &%s[0]\n\t}\n", p.Name, n, p.Name)
	args = append(args, fmt.Sprintf("uintptr(unsafe.Pointer(_p%d))", n), fmt.Sprintf("uintptr(len(%s))", p.Name))
	n++
	} else if p.Type == "int64" && endianness != "" {
	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 if p.Type == "bool" {
	text += fmt.Sprintf("\tvar _p%d uint32\n", n)
	text += fmt.Sprintf("\tif %s {\n\t\t_p%d = 1\n\t} else {\n\t\t_p%d = 0\n\t}\n", p.Name, n, n)
	args = append(args, fmt.Sprintf("uintptr(_p%d)", n))
	n++
	} else {
	args = append(args, fmt.Sprintf("uintptr(%s)", p.Name))
	}
	}
	nargs := len(args)

	// Determine which form to use; pad args with zeros.
	asm := "sysvicall6"
	if nonblock != nil {
	asm = "rawSysvicall6"
	}
	if len(args) <= 6 {
	for len(args) < 6 {
	args = append(args, "0")
	}
	} else {
	fmt.Fprintf(os.Stderr, "%s: too many arguments to system call\n", path)
	os.Exit(1)
	}

	// Actual call.
	arglist := strings.Join(args, ", ")
	call := fmt.Sprintf("%s(uintptr(unsafe.Pointer(&%s)), %d, %s)", asm, sysvarname, nargs, 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" {
	reg = "e1"
	ret[2] = reg
	doErrno = true
	} else {
	reg = fmt.Sprintf("r%d", i)
	ret[i] = reg
	}
	if p.Type == "bool" {
	reg = fmt.Sprintf("%d != 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: not enough registers for int64 return\n", path)
	os.Exit(1)
	}
	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" {
	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 {
	text += fmt.Sprintf("\t%s, %s, %s := %s\n", ret[0], ret[1], ret[2], call)
	}
	text += body

	if doErrno {
	text += "\tif e1 != 0 {\n"
	text += "\t\terr = errnoErr(e1)\n"
	text += "\t}\n"
	}
	text += "\treturn\n"
	text += "}\n"
	}
	if err := s.Err(); err != nil {
	fmt.Fprintf(os.Stderr, err.Error())
	os.Exit(1)
	}
	file.Close()
	}
	imp := ""
	if pack != "unix" {
	imp = "import \"golang.org/x/sys/unix\"\n"
	}

	syscallimp := ""
	if !*illumos {
	syscallimp = "\"syscall\""
	}

	vardecls := "\t" + strings.Join(vars, ",\n\t")
	vardecls += " syscallFunc"
	fmt.Printf(srcTemplate, cmdLine(), goBuildTags(), pack, syscallimp, imp, dynimports, linknames, vardecls, text)
	}

	const srcTemplate = `// %s
	// Code generated by the command above; see README.md. DO NOT EDIT.

	//go:build %s

	package %s

	import (
	"unsafe"
	%s
	)
	%s
	%s
	%s
	var (
	%s
	)

	%s
	`