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// 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
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