1 // Copyright 2016 The Go Authors. All rights reserved.

     2 // Use of this source code is governed by a BSD-style

     3 // license that can be found in the LICENSE file.

     4 

     5 // +build ignore

     6 

     7 // mkpost processes the output of cgo -godefs to

     8 // modify the generated types. It is used to clean up

     9 // the sys API in an architecture specific manner.

    10 //

    11 // mkpost is run after cgo -godefs; see README.md.

    12 package main

    13 

    14 import (

    15 	"bytes"

    16 	"fmt"

    17 	"go/format"

    18 	"io/ioutil"

    19 	"log"

    20 	"os"

    21 	"regexp"

    22 )

    23 

    24 func main() {

    25 	// Get the OS and architecture (using GOARCH_TARGET if it exists)

    26 	goos := os.Getenv("GOOS")

    27 	goarch := os.Getenv("GOARCH_TARGET")

    28 	if goarch == "" {

    29 		goarch = os.Getenv("GOARCH")

    30 	}

    31 	// Check that we are using the new build system if we should be.

    32 	if goos == "linux" && goarch != "sparc64" {

    33 		if os.Getenv("GOLANG_SYS_BUILD") != "docker" {

    34 			os.Stderr.WriteString("In the new build system, mkpost should not be called directly.\n")

    35 			os.Stderr.WriteString("See README.md\n")

    36 			os.Exit(1)

    37 		}

    38 	}

    39 

    40 	b, err := ioutil.ReadAll(os.Stdin)

    41 	if err != nil {

    42 		log.Fatal(err)

    43 	}

    44 

    45 	// Intentionally export __val fields in Fsid and Sigset_t

    46 	valRegex := regexp.MustCompile(`type (Fsid|Sigset_t) struct {(\s+)X__val(\s+\S+\s+)}`)

    47 	b = valRegex.ReplaceAll(b, []byte("type $1 struct {${2}Val$3}"))

    48 

    49 	// If we have empty Ptrace structs, we should delete them. Only s390x emits

    50 	// nonempty Ptrace structs.

    51 	ptraceRexexp := regexp.MustCompile(`type Ptrace((Psw|Fpregs|Per) struct {\s*})`)

    52 	b = ptraceRexexp.ReplaceAll(b, nil)

    53 

    54 	// Replace the control_regs union with a blank identifier for now.

    55 	controlRegsRegex := regexp.MustCompile(`(Control_regs)\s+\[0\]uint64`)

    56 	b = controlRegsRegex.ReplaceAll(b, []byte("_ [0]uint64"))

    57 

    58 	// Remove fields that are added by glibc

    59 	// Note that this is unstable as the identifers are private.

    60 	removeFieldsRegex := regexp.MustCompile(`X__glibc\S*`)

    61 	b = removeFieldsRegex.ReplaceAll(b, []byte("_"))

    62 

    63 	// Convert [65]int8 to [65]byte in Utsname members to simplify

    64 	// conversion to string; see golang.org/issue/20753

    65 	convertUtsnameRegex := regexp.MustCompile(`((Sys|Node|Domain)name|Release|Version|Machine)(\s+)\[(\d+)\]u?int8`)

    66 	b = convertUtsnameRegex.ReplaceAll(b, []byte("$1$3[$4]byte"))

    67 

    68 	// Remove spare fields (e.g. in Statx_t)

    69 	spareFieldsRegex := regexp.MustCompile(`X__spare\S*`)

    70 	b = spareFieldsRegex.ReplaceAll(b, []byte("_"))

    71 

    72 	// Remove cgo padding fields

    73 	removePaddingFieldsRegex := regexp.MustCompile(`Pad_cgo_\d+`)

    74 	b = removePaddingFieldsRegex.ReplaceAll(b, []byte("_"))

    75 

    76 	// Remove padding, hidden, or unused fields

    77 	removeFieldsRegex = regexp.MustCompile(`\b(X_\S+|Padding)`)

    78 	b = removeFieldsRegex.ReplaceAll(b, []byte("_"))

    79 

    80 	// Remove the first line of warning from cgo

    81 	b = b[bytes.IndexByte(b, '\n')+1:]

    82 	// Modify the command in the header to include:

    83 	//  mkpost, our own warning, and a build tag.

    84 	replacement := fmt.Sprintf(`$1 | go run mkpost.go

    85 // Code generated by the command above; see README.md. DO NOT EDIT.

    86 

    87 // +build %s,%s`, goarch, goos)

    88 	cgoCommandRegex := regexp.MustCompile(`(cgo -godefs .*)`)

    89 	b = cgoCommandRegex.ReplaceAll(b, []byte(replacement))

    90 

    91 	// gofmt

    92 	b, err = format.Source(b)

    93 	if err != nil {

    94 		log.Fatal(err)

    95 	}

    96 

    97 	os.Stdout.Write(b)

    98 }