blob: 9feddd00c4b4d018e68fed15380c2a3be4bcd17d [file] [log] [blame]
Scott Baker2d897982019-09-24 11:50:08 -07001// 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.
12package main
13
14import (
15 "bytes"
16 "fmt"
17 "go/format"
18 "io/ioutil"
19 "log"
20 "os"
21 "regexp"
22)
23
24func 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 Docker-based build system if we should be.
32 if goos == "linux" {
33 if os.Getenv("GOLANG_SYS_BUILD") != "docker" {
34 os.Stderr.WriteString("In the Docker-based 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 // Intentionally export __fds_bits field in FdSet
50 fdSetRegex := regexp.MustCompile(`type (FdSet) struct {(\s+)X__fds_bits(\s+\S+\s+)}`)
51 b = fdSetRegex.ReplaceAll(b, []byte("type $1 struct {${2}Bits$3}"))
52
53 // If we have empty Ptrace structs, we should delete them. Only s390x emits
54 // nonempty Ptrace structs.
55 ptraceRexexp := regexp.MustCompile(`type Ptrace((Psw|Fpregs|Per) struct {\s*})`)
56 b = ptraceRexexp.ReplaceAll(b, nil)
57
58 // Replace the control_regs union with a blank identifier for now.
59 controlRegsRegex := regexp.MustCompile(`(Control_regs)\s+\[0\]uint64`)
60 b = controlRegsRegex.ReplaceAll(b, []byte("_ [0]uint64"))
61
62 // Remove fields that are added by glibc
63 // Note that this is unstable as the identifers are private.
64 removeFieldsRegex := regexp.MustCompile(`X__glibc\S*`)
65 b = removeFieldsRegex.ReplaceAll(b, []byte("_"))
66
67 // Convert [65]int8 to [65]byte in Utsname members to simplify
68 // conversion to string; see golang.org/issue/20753
69 convertUtsnameRegex := regexp.MustCompile(`((Sys|Node|Domain)name|Release|Version|Machine)(\s+)\[(\d+)\]u?int8`)
70 b = convertUtsnameRegex.ReplaceAll(b, []byte("$1$3[$4]byte"))
71
72 // Convert [1024]int8 to [1024]byte in Ptmget members
73 convertPtmget := regexp.MustCompile(`([SC]n)(\s+)\[(\d+)\]u?int8`)
74 b = convertPtmget.ReplaceAll(b, []byte("$1[$3]byte"))
75
76 // Remove spare fields (e.g. in Statx_t)
77 spareFieldsRegex := regexp.MustCompile(`X__spare\S*`)
78 b = spareFieldsRegex.ReplaceAll(b, []byte("_"))
79
80 // Remove cgo padding fields
81 removePaddingFieldsRegex := regexp.MustCompile(`Pad_cgo_\d+`)
82 b = removePaddingFieldsRegex.ReplaceAll(b, []byte("_"))
83
84 // Remove padding, hidden, or unused fields
85 removeFieldsRegex = regexp.MustCompile(`\b(X_\S+|Padding)`)
86 b = removeFieldsRegex.ReplaceAll(b, []byte("_"))
87
88 // Remove the first line of warning from cgo
89 b = b[bytes.IndexByte(b, '\n')+1:]
90 // Modify the command in the header to include:
91 // mkpost, our own warning, and a build tag.
92 replacement := fmt.Sprintf(`$1 | go run mkpost.go
93// Code generated by the command above; see README.md. DO NOT EDIT.
94
95// +build %s,%s`, goarch, goos)
96 cgoCommandRegex := regexp.MustCompile(`(cgo -godefs .*)`)
97 b = cgoCommandRegex.ReplaceAll(b, []byte(replacement))
98
99 // gofmt
100 b, err = format.Source(b)
101 if err != nil {
102 log.Fatal(err)
103 }
104
105 os.Stdout.Write(b)
106}