blob: d5634b1c28f9806e52feabd6b45988e438033f14 [file] [log] [blame]
// 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
// +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, ",", " && ")
}
// plusBuildTags returns build tags in the +build format.
func plusBuildTags() 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_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.
// 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 = 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(), plusBuildTags(), 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
// +build %s
package %s
import (
"unsafe"
%s
)
%s
%s
%s
var (
%s
)
%s
`