407 lines
12 KiB
Go
407 lines
12 KiB
Go
// 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") {
|
|
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
|
|
if sysname == "getdirentries64" {
|
|
// Special case - libSystem name and
|
|
// raw syscall name don't match.
|
|
sysname = "__getdirentries64"
|
|
}
|
|
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
|
|
`
|